Prefer final

Declaring variables as final when possible is a good practice
because it helps avoid accidental reassignments and allows the
compiler to do optimizations.

analysis_options.yaml

@@ -3,7 +3,6 @@ include: package:pedantic/analysis_options.yaml
 analyzer:
   errors:
     undefined_prefixed_name: ignore
-    omit_local_variable_types: ignore
     unsafe_html: ignore
 linter:
   rules:
@@ -11,7 +10,11 @@ linter:
     - avoid_print
     - avoid_redundant_argument_values
     - directives_ordering
+    - omit_local_variable_types
     - prefer_const_constructors
     - prefer_const_constructors_in_immutables
+    - prefer_final_fields
+    - prefer_final_in_for_each
+    - prefer_final_locals
     - prefer_relative_imports
     - unnecessary_parenthesis

example/lib/pages/home_page.dart

@@ -178,14 +178,14 @@ class _HomePageState extends State<HomePage> {
   // You can also upload the picked image to any server (eg : AWS s3 or Firebase) and then return the uploaded image URL
   Future<String> _onImagePickCallback(File file) async {
     // Copies the picked file from temporary cache to applications directory
-    Directory appDocDir = await getApplicationDocumentsDirectory();
-    File copiedFile =
+    final appDocDir = await getApplicationDocumentsDirectory();
+    final copiedFile =
         await file.copy('${appDocDir.path}/${basename(file.path)}');
     return copiedFile.path.toString();
   }
 
   Widget _buildMenuBar(BuildContext context) {
-    Size size = MediaQuery.of(context).size;
+    final size = MediaQuery.of(context).size;
     final itemStyle = const TextStyle(
       color: Colors.white,
       fontSize: 18,

example/lib/universal_ui/universal_ui.dart

@@ -28,8 +28,8 @@ var ui = UniversalUI();
 Widget defaultEmbedBuilderWeb(BuildContext context, leaf.Embed node) {
   switch (node.value.type) {
     case 'image':
-      String imageUrl = node.value.data;
-      Size size = MediaQuery.of(context).size;
+      final String imageUrl = node.value.data;
+      final size = MediaQuery.of(context).size;
       UniversalUI().platformViewRegistry.registerViewFactory(
           imageUrl, (int viewId) => html.ImageElement()..src = imageUrl);
       return Padding(

lib/models/documents/attribute.dart

@@ -164,8 +164,8 @@ class Attribute<T> {
     if (!_registry.containsKey(key)) {
       throw ArgumentError.value(key, 'key "$key" not found.');
     }
-    Attribute origin = _registry[key]!;
-    Attribute attribute = clone(origin, value);
+    final origin = _registry[key]!;
+    final attribute = clone(origin, value);
     return attribute;
   }
 
@@ -177,7 +177,7 @@ class Attribute<T> {
   bool operator ==(Object other) {
     if (identical(this, other)) return true;
     if (other is! Attribute<T>) return false;
-    Attribute<T> typedOther = other;
+    final typedOther = other;
     return key == typedOther.key &&
         scope == typedOther.scope &&
         value == typedOther.value;

lib/models/documents/document.dart

@@ -56,14 +56,14 @@ class Document {
       return Delta();
     }
 
-    Delta delta = _rules.apply(RuleType.INSERT, this, index, data: data);
+    final delta = _rules.apply(RuleType.INSERT, this, index, data: data);
     compose(delta, ChangeSource.LOCAL);
     return delta;
   }
 
   Delta delete(int index, int len) {
     assert(index >= 0 && len > 0);
-    Delta delta = _rules.apply(RuleType.DELETE, this, index, len: len);
+    final delta = _rules.apply(RuleType.DELETE, this, index, len: len);
     if (delta.isNotEmpty) {
       compose(delta, ChangeSource.LOCAL);
     }
@@ -74,18 +74,18 @@ class Document {
     assert(index >= 0);
     assert(data is String || data is Embeddable);
 
-    bool dataIsNotEmpty = (data is String) ? data.isNotEmpty : true;
+    final dataIsNotEmpty = (data is String) ? data.isNotEmpty : true;
 
     assert(dataIsNotEmpty || len > 0);
 
-    Delta delta = Delta();
+    var delta = Delta();
 
     if (dataIsNotEmpty) {
       delta = insert(index + len, data);
     }
 
     if (len > 0) {
-      Delta deleteDelta = delete(index, len);
+      final deleteDelta = delete(index, len);
       delta = delta.compose(deleteDelta);
     }
 
@@ -95,9 +95,9 @@ class Document {
   Delta format(int index, int len, Attribute? attribute) {
     assert(index >= 0 && len >= 0 && attribute != null);
 
-    Delta delta = Delta();
+    var delta = Delta();
 
-    Delta formatDelta = _rules.apply(RuleType.FORMAT, this, index,
+    final formatDelta = _rules.apply(RuleType.FORMAT, this, index,
         len: len, attribute: attribute);
     if (formatDelta.isNotEmpty) {
       compose(formatDelta, ChangeSource.LOCAL);
@@ -108,16 +108,16 @@ class Document {
   }
 
   Style collectStyle(int index, int len) {
-    ChildQuery res = queryChild(index);
+    final res = queryChild(index);
     return (res.node as Line).collectStyle(res.offset, len);
   }
 
   ChildQuery queryChild(int offset) {
-    ChildQuery res = _root.queryChild(offset, true);
+    final res = _root.queryChild(offset, true);
     if (res.node is Line) {
       return res;
     }
-    Block block = res.node as Block;
+    final block = res.node as Block;
     return block.queryChild(res.offset, true);
   }
 
@@ -126,11 +126,11 @@ class Document {
     delta.trim();
     assert(delta.isNotEmpty);
 
-    int offset = 0;
+    var offset = 0;
     delta = _transform(delta);
-    Delta originalDelta = toDelta();
-    for (Operation op in delta.toList()) {
-      Style? style =
+    final originalDelta = toDelta();
+    for (final op in delta.toList()) {
+      final style =
           op.attributes != null ? Style.fromJson(op.attributes) : null;
 
       if (op.isInsert) {
@@ -172,10 +172,10 @@ class Document {
   bool get hasRedo => _history.hasRedo;
 
   static Delta _transform(Delta delta) {
-    Delta res = Delta();
-    List<Operation> ops = delta.toList();
-    for (int i = 0; i < ops.length; i++) {
-      Operation op = ops[i];
+    final res = Delta();
+    final ops = delta.toList();
+    for (var i = 0; i < ops.length; i++) {
+      final op = ops[i];
       res.push(op);
       _handleImageInsert(i, ops, op, res);
     }
@@ -184,14 +184,14 @@ class Document {
 
   static void _handleImageInsert(
       int i, List<Operation> ops, Operation op, Delta res) {
-    bool nextOpIsImage =
+    final nextOpIsImage =
         i + 1 < ops.length && ops[i + 1].isInsert && ops[i + 1].data is! String;
     if (nextOpIsImage && !(op.data as String).endsWith('\n')) {
       res.push(Operation.insert('\n'));
     }
     // Currently embed is equivalent to image and hence `is! String`
-    bool opInsertImage = op.isInsert && op.data is! String;
-    bool nextOpIsLineBreak = i + 1 < ops.length &&
+    final opInsertImage = op.isInsert && op.data is! String;
+    final nextOpIsLineBreak = i + 1 < ops.length &&
         ops[i + 1].isInsert &&
         ops[i + 1].data is String &&
         (ops[i + 1].data as String).startsWith('\n');
@@ -221,7 +221,7 @@ class Document {
 
   void _loadDocument(Delta doc) {
     assert((doc.last.data as String).endsWith('\n'));
-    int offset = 0;
+    var offset = 0;
     for (final op in doc.toList()) {
       if (!op.isInsert) {
         throw ArgumentError.value(doc,
@@ -247,12 +247,12 @@ class Document {
       return false;
     }
 
-    final Node node = root.children.first;
+    final node = root.children.first;
     if (!node.isLast) {
       return false;
     }
 
-    Delta delta = node.toDelta();
+    final delta = node.toDelta();
     return delta.length == 1 &&
         delta.first.data == '\n' &&
         delta.first.key == 'insert';

lib/models/documents/history.dart

@@ -47,7 +47,7 @@ class History {
   void record(Delta change, Delta before) {
     if (change.isEmpty) return;
     stack.redo.clear();
-    Delta undoDelta = change.invert(before);
+    var undoDelta = change.invert(before);
     final timeStamp = DateTime.now().millisecondsSinceEpoch;
 
     if (lastRecorded + interval > timeStamp && stack.undo.isNotEmpty) {
@@ -74,7 +74,7 @@ class History {
   }
 
   void transformStack(List<Delta> stack, Delta delta) {
-    for (int i = stack.length - 1; i >= 0; i -= 1) {
+    for (var i = stack.length - 1; i >= 0; i -= 1) {
       final oldDelta = stack[i];
       stack[i] = delta.transform(oldDelta, true);
       delta = oldDelta.transform(delta, false);
@@ -88,10 +88,10 @@ class History {
     if (source.isEmpty) {
       return const Tuple2(false, 0);
     }
-    Delta delta = source.removeLast();
+    final delta = source.removeLast();
     // look for insert or delete
     int? len = 0;
-    List<Operation> ops = delta.toList();
+    final ops = delta.toList();
     for (var i = 0; i < ops.length; i++) {
       if (ops[i].key == Operation.insertKey) {
         len = ops[i].length;
@@ -99,8 +99,8 @@ class History {
         len = ops[i].length! * -1;
       }
     }
-    Delta base = Delta.from(doc.toDelta());
-    Delta inverseDelta = delta.invert(base);
+    final base = Delta.from(doc.toDelta());
+    final inverseDelta = delta.invert(base);
     dest.add(inverseDelta);
     lastRecorded = 0;
     ignoreChange = true;

lib/models/documents/nodes/block.dart

@@ -17,7 +17,7 @@ class Block extends Container<Line?> {
   @override
   void adjust() {
     if (isEmpty) {
-      Node? sibling = previous;
+      final sibling = previous;
       unlink();
       if (sibling != null) {
         sibling.adjust();
@@ -25,8 +25,8 @@ class Block extends Container<Line?> {
       return;
     }
 
-    Block block = this;
-    Node? prev = block.previous;
+    var block = this;
+    final prev = block.previous;
     // merging it with previous block if style is the same
     if (!block.isFirst &&
         block.previous is Block &&
@@ -35,7 +35,7 @@ class Block extends Container<Line?> {
       block.unlink();
       block = prev as Block;
     }
-    Node? next = block.next;
+    final next = block.next;
     // merging it with next block if style is the same
     if (!block.isLast && block.next is Block && next!.style == block.style) {
       (next as Block).moveChildToNewParent(block);
@@ -47,7 +47,7 @@ class Block extends Container<Line?> {
   String toString() {
     final block = style.attributes.toString();
     final buffer = StringBuffer('§ {$block}\n');
-    for (var child in children) {
+    for (final child in children) {
       final tree = child.isLast ? '└' : '├';
       buffer.write('  $tree $child');
       if (!child.isLast) buffer.writeln();

lib/models/documents/nodes/container.dart

@@ -48,9 +48,9 @@ abstract class Container<T extends Node?> extends Node {
       return;
     }
 
-    T? last = newParent!.isEmpty ? null : newParent.last as T?;
+    final last = newParent!.isEmpty ? null : newParent.last as T?;
     while (isNotEmpty) {
-      T child = first as T;
+      final child = first as T;
       child?.unlink();
       newParent.add(child);
     }
@@ -63,8 +63,8 @@ abstract class Container<T extends Node?> extends Node {
       return ChildQuery(null, 0);
     }
 
-    for (Node node in children) {
-      int len = node.length;
+    for (final node in children) {
+      final len = node.length;
       if (offset < len || (inclusive && offset == len && (node.isLast))) {
         return ChildQuery(node, offset);
       }
@@ -84,14 +84,14 @@ abstract class Container<T extends Node?> extends Node {
     assert(index == 0 || (index > 0 && index < length));
 
     if (isNotEmpty) {
-      ChildQuery child = queryChild(index, false);
+      final child = queryChild(index, false);
       child.node!.insert(child.offset, data, style);
       return;
     }
 
     // empty
     assert(index == 0);
-    T node = defaultChild;
+    final node = defaultChild;
     add(node);
     node?.insert(index, data, style);
   }
@@ -99,14 +99,14 @@ abstract class Container<T extends Node?> extends Node {
   @override
   void retain(int index, int? length, Style? attributes) {
     assert(isNotEmpty);
-    ChildQuery child = queryChild(index, false);
+    final child = queryChild(index, false);
     child.node!.retain(child.offset, length, attributes);
   }
 
   @override
   void delete(int index, int? length) {
     assert(isNotEmpty);
-    ChildQuery child = queryChild(index, false);
+    final child = queryChild(index, false);
     child.node!.delete(child.offset, length);
   }
 

lib/models/documents/nodes/embed.dart

@@ -5,12 +5,12 @@ class Embeddable {
   Embeddable(this.type, this.data);
 
   Map<String, dynamic> toJson() {
-    Map<String, String> m = {type: data};
+    final m = <String, String>{type: data};
     return m;
   }
 
   static Embeddable fromJson(Map<String, dynamic> json) {
-    Map<String, dynamic> m = Map<String, dynamic>.from(json);
+    final m = Map<String, dynamic>.from(json);
     assert(m.length == 1, 'Embeddable map has one key');
 
     return BlockEmbed(m.keys.first, m.values.first);

lib/models/documents/nodes/leaf.dart

@@ -18,7 +18,7 @@ abstract class Leaf extends Node {
     if (data is Embeddable) {
       return Embed(data);
     }
-    String text = data as String;
+    final text = data as String;
     assert(text.isNotEmpty);
     return Text(text);
   }
@@ -44,14 +44,15 @@ abstract class Leaf extends Node {
 
   @override
   Delta toDelta() {
-    var data = _value is Embeddable ? (_value as Embeddable).toJson() : _value;
+    final data =
+        _value is Embeddable ? (_value as Embeddable).toJson() : _value;
     return Delta()..insert(data, style.toJson());
   }
 
   @override
   void insert(int index, Object data, Style? style) {
     assert(index >= 0 && index <= length);
-    Leaf node = Leaf(data);
+    final node = Leaf(data);
     if (index < length) {
       splitAt(index)!.insertBefore(node);
     } else {
@@ -66,9 +67,9 @@ abstract class Leaf extends Node {
       return;
     }
 
-    int local = math.min(length - index, len!);
-    int remain = len - local;
-    Leaf node = _isolate(index, local);
+    final local = math.min(length - index, len!);
+    final remain = len - local;
+    final node = _isolate(index, local);
 
     if (remain > 0) {
       assert(node.next != null);
@@ -81,13 +82,13 @@ abstract class Leaf extends Node {
   void delete(int index, int? len) {
     assert(index < length);
 
-    int local = math.min(length - index, len!);
-    Leaf target = _isolate(index, local);
-    Leaf? prev = target.previous as Leaf?;
-    Leaf? next = target.next as Leaf?;
+    final local = math.min(length - index, len!);
+    final target = _isolate(index, local);
+    final prev = target.previous as Leaf?;
+    final next = target.next as Leaf?;
     target.unlink();
 
-    int remain = len - local;
+    final remain = len - local;
     if (remain > 0) {
       assert(next != null);
       next!.delete(0, remain);
@@ -104,9 +105,9 @@ abstract class Leaf extends Node {
       return;
     }
 
-    Text node = this as Text;
+    var node = this as Text;
     // merging it with previous node if style is the same
-    Node? prev = node.previous;
+    final prev = node.previous;
     if (!node.isFirst && prev is Text && prev.style == node.style) {
       prev._value = prev.value + node.value;
       node.unlink();
@@ -114,7 +115,7 @@ abstract class Leaf extends Node {
     }
 
     // merging it with next node if style is the same
-    Node? next = node.next;
+    final next = node.next;
     if (!node.isLast && next is Text && next.style == node.style) {
       node._value = node.value + next.value;
       next.unlink();
@@ -123,7 +124,7 @@ abstract class Leaf extends Node {
 
   Leaf? cutAt(int index) {
     assert(index >= 0 && index <= length);
-    Leaf? cut = splitAt(index);
+    final cut = splitAt(index);
     cut?.unlink();
     return cut;
   }
@@ -138,9 +139,9 @@ abstract class Leaf extends Node {
     }
 
     assert(this is Text);
-    String text = _value as String;
+    final text = _value as String;
     _value = text.substring(0, index);
-    Leaf split = Leaf(text.substring(index));
+    final split = Leaf(text.substring(index));
     split.applyStyle(style);
     insertAfter(split);
     return split;
@@ -157,7 +158,7 @@ abstract class Leaf extends Node {
   Leaf _isolate(int index, int length) {
     assert(
         index >= 0 && index < this.length && (index + length <= this.length));
-    Leaf target = splitAt(index)!;
+    final target = splitAt(index)!;
     target.splitAt(length);
     return target;
   }

lib/models/documents/nodes/line.dart

@@ -47,7 +47,7 @@ class Line extends Container<Leaf?> {
         .fold(Delta(), (dynamic a, b) => a.concat(b));
     var attributes = style;
     if (parent is Block) {
-      Block block = parent as Block;
+      final block = parent as Block;
       attributes = attributes.mergeAll(block.style);
     }
     delta.insert('\n', attributes.toJson());
@@ -71,20 +71,20 @@ class Line extends Container<Leaf?> {
       return;
     }
 
-    String text = data as String;
-    int lineBreak = text.indexOf('\n');
+    final text = data as String;
+    final lineBreak = text.indexOf('\n');
     if (lineBreak < 0) {
       _insert(index, text, style);
       return;
     }
 
-    String prefix = text.substring(0, lineBreak);
+    final prefix = text.substring(0, lineBreak);
     _insert(index, prefix, style);
     if (prefix.isNotEmpty) {
       index += prefix.length;
     }
 
-    Line nextLine = _getNextLine(index);
+    final nextLine = _getNextLine(index);
 
     clearStyle();
 
@@ -95,7 +95,7 @@ class Line extends Container<Leaf?> {
     _format(style);
 
     // Continue with the remaining
-    String remain = text.substring(lineBreak + 1);
+    final remain = text.substring(lineBreak + 1);
     nextLine.insert(0, remain, style);
   }
 
@@ -104,9 +104,9 @@ class Line extends Container<Leaf?> {
     if (style == null) {
       return;
     }
-    int thisLen = length;
+    final thisLen = length;
 
-    int local = math.min(thisLen - index, len!);
+    final local = math.min(thisLen - index, len!);
 
     if (index + local == thisLen && local == 1) {
       assert(style.values.every((attr) => attr.scope == AttributeScope.BLOCK));
@@ -117,7 +117,7 @@ class Line extends Container<Leaf?> {
       super.retain(index, local, style);
     }
 
-    int remain = len - local;
+    final remain = len - local;
     if (remain > 0) {
       assert(nextLine != null);
       nextLine!.retain(0, remain, style);
@@ -126,8 +126,8 @@ class Line extends Container<Leaf?> {
 
   @override
   void delete(int index, int? len) {
-    int local = math.min(length - index, len!);
-    bool deleted = index + local == length;
+    final local = math.min(length - index, len!);
+    final deleted = index + local == length;
     if (deleted) {
       clearStyle();
       if (local > 1) {
@@ -137,7 +137,7 @@ class Line extends Container<Leaf?> {
       super.delete(index, local);
     }
 
-    int remain = len - local;
+    final remain = len - local;
     if (remain > 0) {
       assert(nextLine != null);
       nextLine!.delete(0, remain);
@@ -150,7 +150,7 @@ class Line extends Container<Leaf?> {
     }
 
     if (deleted) {
-      Node p = parent!;
+      final Node p = parent!;
       unlink();
       p.adjust();
     }
@@ -162,24 +162,24 @@ class Line extends Container<Leaf?> {
     }
 
     applyStyle(newStyle);
-    Attribute? blockStyle = newStyle.getBlockExceptHeader();
+    final blockStyle = newStyle.getBlockExceptHeader();
     if (blockStyle == null) {
       return;
     }
 
     if (parent is Block) {
-      Attribute? parentStyle = (parent as Block).style.getBlockExceptHeader();
+      final parentStyle = (parent as Block).style.getBlockExceptHeader();
       if (blockStyle.value == null) {
         _unwrap();
       } else if (blockStyle != parentStyle) {
         _unwrap();
-        Block block = Block();
+        final block = Block();
         block.applyAttribute(blockStyle);
         _wrap(block);
         block.adjust();
       }
     } else if (blockStyle.value != null) {
-      Block block = Block();
+      final block = Block();
       block.applyAttribute(blockStyle);
       _wrap(block);
       block.adjust();
@@ -197,7 +197,7 @@ class Line extends Container<Leaf?> {
     if (parent is! Block) {
       throw ArgumentError('Invalid parent');
     }
-    Block block = parent as Block;
+    final block = parent as Block;
 
     assert(block.children.contains(this));
 
@@ -208,10 +208,10 @@ class Line extends Container<Leaf?> {
       unlink();
       block.insertAfter(this);
     } else {
-      Block before = block.clone() as Block;
+      final before = block.clone() as Block;
       block.insertBefore(before);
 
-      Line child = block.first as Line;
+      var child = block.first as Line;
       while (child != this) {
         child.unlink();
         before.add(child);
@@ -226,20 +226,20 @@ class Line extends Container<Leaf?> {
   Line _getNextLine(int index) {
     assert(index == 0 || (index > 0 && index < length));
 
-    Line line = clone() as Line;
+    final line = clone() as Line;
     insertAfter(line);
     if (index == length - 1) {
       return line;
     }
 
-    ChildQuery query = queryChild(index, false);
+    final query = queryChild(index, false);
     while (!query.node!.isLast) {
-      Leaf next = last as Leaf;
+      final next = last as Leaf;
       next.unlink();
       line.addFirst(next);
     }
-    Leaf child = query.node as Leaf;
-    Leaf? cut = child.splitAt(query.offset);
+    final child = query.node as Leaf;
+    final cut = child.splitAt(query.offset);
     cut?.unlink();
     line.addFirst(cut);
     return line;
@@ -256,12 +256,12 @@ class Line extends Container<Leaf?> {
     }
 
     if (isNotEmpty) {
-      ChildQuery result = queryChild(index, true);
+      final result = queryChild(index, true);
       result.node!.insert(result.offset, data, style);
       return;
     }
 
-    Leaf child = Leaf(data);
+    final child = Leaf(data);
     add(child);
     child.format(style);
   }
@@ -272,30 +272,30 @@ class Line extends Container<Leaf?> {
   }
 
   Style collectStyle(int offset, int len) {
-    int local = math.min(length - offset, len);
-    Style res = Style();
-    var excluded = <Attribute>{};
+    final local = math.min(length - offset, len);
+    var res = Style();
+    final excluded = <Attribute>{};
 
     void _handle(Style style) {
       if (res.isEmpty) {
         excluded.addAll(style.values);
       } else {
-        for (Attribute attr in res.values) {
+        for (final attr in res.values) {
           if (!style.containsKey(attr.key)) {
             excluded.add(attr);
           }
         }
       }
-      Style remain = style.removeAll(excluded);
+      final remain = style.removeAll(excluded);
       res = res.removeAll(excluded);
       res = res.mergeAll(remain);
     }
 
-    ChildQuery data = queryChild(offset, true);
-    Leaf? node = data.node as Leaf?;
+    final data = queryChild(offset, true);
+    var node = data.node as Leaf?;
     if (node != null) {
       res = res.mergeAll(node.style);
-      int pos = node.length - data.offset;
+      var pos = node.length - data.offset;
       while (!node!.isLast && pos < local) {
         node = node.next as Leaf?;
         _handle(node!.style);
@@ -305,11 +305,11 @@ class Line extends Container<Leaf?> {
 
     res = res.mergeAll(style);
     if (parent is Block) {
-      Block block = parent as Block;
+      final block = parent as Block;
       res = res.mergeAll(block.style);
     }
 
-    int remain = len - local;
+    final remain = len - local;
     if (remain > 0) {
       _handle(nextLine!.collectStyle(0, remain));
     }

lib/models/documents/nodes/node.dart

@@ -32,19 +32,19 @@ abstract class Node extends LinkedListEntry<Node> {
   int get length;
 
   Node clone() {
-    Node node = newInstance();
+    final node = newInstance();
     node.applyStyle(style);
     return node;
   }
 
   int getOffset() {
-    int offset = 0;
+    var offset = 0;
 
     if (list == null || isFirst) {
       return offset;
     }
 
-    Node cur = this;
+    var cur = this;
     do {
       cur = cur.previous!;
       offset += cur.length;

lib/models/documents/style.dart

@@ -16,8 +16,8 @@ class Style {
       return Style();
     }
 
-    Map<String, Attribute> result = attributes.map((String key, dynamic value) {
-      Attribute attr = Attribute.fromKeyValue(key, value);
+    final result = attributes.map((String key, dynamic value) {
+      final attr = Attribute.fromKeyValue(key, value);
       return MapEntry<String, Attribute>(key, attr);
     });
     return Style.attr(result);
@@ -48,7 +48,7 @@ class Style {
   bool containsKey(String key) => _attributes.containsKey(key);
 
   Attribute? getBlockExceptHeader() {
-    for (Attribute val in values) {
+    for (final val in values) {
       if (val.isBlockExceptHeader) {
         return val;
       }
@@ -57,7 +57,7 @@ class Style {
   }
 
   Style merge(Attribute attribute) {
-    Map<String, Attribute> merged = Map<String, Attribute>.from(_attributes);
+    final merged = Map<String, Attribute>.from(_attributes);
     if (attribute.value == null) {
       merged.remove(attribute.key);
     } else {
@@ -67,21 +67,21 @@ class Style {
   }
 
   Style mergeAll(Style other) {
-    Style result = Style.attr(_attributes);
-    for (Attribute attribute in other.values) {
+    var result = Style.attr(_attributes);
+    for (final attribute in other.values) {
       result = result.merge(attribute);
     }
     return result;
   }
 
   Style removeAll(Set<Attribute> attributes) {
-    Map<String, Attribute> merged = Map<String, Attribute>.from(_attributes);
+    final merged = Map<String, Attribute>.from(_attributes);
     attributes.map((item) => item.key).forEach(merged.remove);
     return Style.attr(merged);
   }
 
   Style put(Attribute attribute) {
-    Map<String, Attribute> m = Map<String, Attribute>.from(attributes);
+    final m = Map<String, Attribute>.from(attributes);
     m[attribute.key] = attribute;
     return Style.attr(m);
   }
@@ -94,7 +94,7 @@ class Style {
     if (other is! Style) {
       return false;
     }
-    Style typedOther = other;
+    final typedOther = other;
     final eq = const MapEquality<String, Attribute>();
     return eq.equals(_attributes, typedOther._attributes);
   }

lib/models/quill_delta.dart

@@ -135,7 +135,7 @@ class Operation {
   bool operator ==(other) {
     if (identical(this, other)) return true;
     if (other is! Operation) return false;
-    Operation typedOther = other;
+    final typedOther = other;
     return key == typedOther.key &&
         length == typedOther.length &&
         _valueEquality.equals(data, typedOther.data) &&
@@ -221,14 +221,14 @@ class Delta {
     attr ??= const {};
     base ??= const {};
 
-    var baseInverted = base.keys.fold({}, (dynamic memo, key) {
+    final baseInverted = base.keys.fold({}, (dynamic memo, key) {
       if (base![key] != attr![key] && attr.containsKey(key)) {
         memo[key] = base[key];
       }
       return memo;
     });
 
-    var inverted =
+    final inverted =
         Map<String, dynamic>.from(attr.keys.fold(baseInverted, (memo, key) {
       if (base![key] != attr![key] && !base.containsKey(key)) {
         memo[key] = null;
@@ -292,7 +292,7 @@ class Delta {
   bool operator ==(dynamic other) {
     if (identical(this, other)) return true;
     if (other is! Delta) return false;
-    Delta typedOther = other;
+    final typedOther = other;
     final comparator =
         const ListEquality<Operation>(DefaultEquality<Operation>());
     return comparator.equals(_operations, typedOther._operations);
@@ -529,7 +529,8 @@ class Delta {
           if (op.isDelete) {
             inverted.push(baseOp);
           } else if (op.isRetain && op.isNotPlain) {
-            var invertAttr = invertAttributes(op.attributes, baseOp.attributes);
+            final invertAttr =
+                invertAttributes(op.attributes, baseOp.attributes);
             inverted.retain(
                 baseOp.length!, invertAttr.isEmpty ? null : invertAttr);
           }
@@ -548,7 +549,7 @@ class Delta {
   Delta slice(int start, [int? end]) {
     final delta = Delta();
     var index = 0;
-    var opIterator = DeltaIterator(this);
+    final opIterator = DeltaIterator(this);
 
     final actualEnd = end ?? double.infinity;
 
@@ -661,7 +662,7 @@ class DeltaIterator {
       final opIsNotEmpty =
           opData is String ? opData.isNotEmpty : true; // embeds are never empty
       final opLength = opData is String ? opData.length : 1;
-      final int opActualLength = opIsNotEmpty ? opLength : actualLength as int;
+      final opActualLength = opIsNotEmpty ? opLength : actualLength as int;
       return Operation._(opKey, opActualLength, opData, opAttributes);
     }
     return Operation.retain(length);

lib/models/rules/delete.dart

@@ -34,31 +34,31 @@ class PreserveLineStyleOnMergeRule extends DeleteRule {
   @override
   Delta? applyRule(Delta document, int index,
       {int? len, Object? data, Attribute? attribute}) {
-    DeltaIterator itr = DeltaIterator(document);
+    final itr = DeltaIterator(document);
     itr.skip(index);
-    Operation op = itr.next(1);
+    var op = itr.next(1);
     if (op.data != '\n') {
       return null;
     }
 
-    bool isNotPlain = op.isNotPlain;
-    Map<String, dynamic>? attrs = op.attributes;
+    final isNotPlain = op.isNotPlain;
+    final attrs = op.attributes;
 
     itr.skip(len! - 1);
-    Delta delta = Delta()
+    final delta = Delta()
       ..retain(index)
       ..delete(len);
 
     while (itr.hasNext) {
       op = itr.next();
-      String text = op.data is String ? (op.data as String?)! : '';
-      int lineBreak = text.indexOf('\n');
+      final text = op.data is String ? (op.data as String?)! : '';
+      final lineBreak = text.indexOf('\n');
       if (lineBreak == -1) {
         delta.retain(op.length!);
         continue;
       }
 
-      Map<String, dynamic>? attributes = op.attributes == null
+      var attributes = op.attributes == null
           ? null
           : op.attributes!.map<String, dynamic>((String key, dynamic value) =>
               MapEntry<String, dynamic>(key, null));
@@ -80,15 +80,15 @@ class EnsureEmbedLineRule extends DeleteRule {
   @override
   Delta? applyRule(Delta document, int index,
       {int? len, Object? data, Attribute? attribute}) {
-    DeltaIterator itr = DeltaIterator(document);
+    final itr = DeltaIterator(document);
 
-    Operation? op = itr.skip(index);
+    var op = itr.skip(index);
     int? indexDelta = 0, lengthDelta = 0, remain = len;
-    bool embedFound = op != null && op.data is! String;
-    bool hasLineBreakBefore =
+    var embedFound = op != null && op.data is! String;
+    final hasLineBreakBefore =
         !embedFound && (op == null || (op.data as String).endsWith('\n'));
     if (embedFound) {
-      Operation candidate = itr.next(1);
+      var candidate = itr.next(1);
       if (remain != null) {
         remain--;
         if (candidate.data == '\n') {
@@ -107,7 +107,7 @@ class EnsureEmbedLineRule extends DeleteRule {
     op = itr.skip(remain!);
     if (op != null &&
         (op.data is String ? op.data as String? : '')!.endsWith('\n')) {
-      Operation candidate = itr.next(1);
+      final candidate = itr.next(1);
       if (candidate.data is! String && !hasLineBreakBefore) {
         embedFound = true;
         lengthDelta--;

lib/models/rules/format.dart

@@ -26,21 +26,21 @@ class ResolveLineFormatRule extends FormatRule {
       return null;
     }
 
-    Delta delta = Delta()..retain(index);
-    DeltaIterator itr = DeltaIterator(document);
+    var delta = Delta()..retain(index);
+    final itr = DeltaIterator(document);
     itr.skip(index);
     Operation op;
-    for (int cur = 0; cur < len! && itr.hasNext; cur += op.length!) {
+    for (var cur = 0; cur < len! && itr.hasNext; cur += op.length!) {
       op = itr.next(len - cur);
       if (op.data is! String || !(op.data as String).contains('\n')) {
         delta.retain(op.length!);
         continue;
       }
-      String text = op.data as String;
-      Delta tmp = Delta();
-      int offset = 0;
+      final text = op.data as String;
+      final tmp = Delta();
+      var offset = 0;
 
-      for (int lineBreak = text.indexOf('\n');
+      for (var lineBreak = text.indexOf('\n');
           lineBreak >= 0;
           lineBreak = text.indexOf('\n', offset)) {
         tmp..retain(lineBreak - offset)..retain(1, attribute.toJson());
@@ -52,8 +52,8 @@ class ResolveLineFormatRule extends FormatRule {
 
     while (itr.hasNext) {
       op = itr.next();
-      String text = op.data is String ? (op.data as String?)! : '';
-      int lineBreak = text.indexOf('\n');
+      final text = op.data is String ? (op.data as String?)! : '';
+      final lineBreak = text.indexOf('\n');
       if (lineBreak < 0) {
         delta.retain(op.length!);
         continue;
@@ -75,9 +75,9 @@ class FormatLinkAtCaretPositionRule extends FormatRule {
       return null;
     }
 
-    Delta delta = Delta();
-    DeltaIterator itr = DeltaIterator(document);
-    Operation? before = itr.skip(index), after = itr.next();
+    final delta = Delta();
+    final itr = DeltaIterator(document);
+    final before = itr.skip(index), after = itr.next();
     int? beg = index, retain = 0;
     if (before != null && before.hasAttribute(attribute.key)) {
       beg -= before.length!;
@@ -105,20 +105,20 @@ class ResolveInlineFormatRule extends FormatRule {
       return null;
     }
 
-    Delta delta = Delta()..retain(index);
-    DeltaIterator itr = DeltaIterator(document);
+    final delta = Delta()..retain(index);
+    final itr = DeltaIterator(document);
     itr.skip(index);
 
     Operation op;
-    for (int cur = 0; cur < len! && itr.hasNext; cur += op.length!) {
+    for (var cur = 0; cur < len! && itr.hasNext; cur += op.length!) {
       op = itr.next(len - cur);
-      String text = op.data is String ? (op.data as String?)! : '';
-      int lineBreak = text.indexOf('\n');
+      final text = op.data is String ? (op.data as String?)! : '';
+      var lineBreak = text.indexOf('\n');
       if (lineBreak < 0) {
         delta.retain(op.length!, attribute.toJson());
         continue;
       }
-      int pos = 0;
+      var pos = 0;
       while (lineBreak >= 0) {
         delta..retain(lineBreak - pos, attribute.toJson())..retain(1);
         pos = lineBreak + 1;

lib/models/rules/insert.dart

@@ -29,28 +29,28 @@ class PreserveLineStyleOnSplitRule extends InsertRule {
       return null;
     }
 
-    DeltaIterator itr = DeltaIterator(document);
-    Operation? before = itr.skip(index);
+    final itr = DeltaIterator(document);
+    final before = itr.skip(index);
     if (before == null ||
         before.data is! String ||
         (before.data as String).endsWith('\n')) {
       return null;
     }
-    Operation after = itr.next();
+    final after = itr.next();
     if (after.data is! String || (after.data as String).startsWith('\n')) {
       return null;
     }
 
     final text = after.data as String;
 
-    Delta delta = Delta()..retain(index);
+    final delta = Delta()..retain(index);
     if (text.contains('\n')) {
       assert(after.isPlain);
       delta.insert('\n');
       return delta;
     }
-    Tuple2<Operation?, int?> nextNewLine = _getNextNewLine(itr);
-    Map<String, dynamic>? attributes = nextNewLine.item1?.attributes;
+    final nextNewLine = _getNextNewLine(itr);
+    final attributes = nextNewLine.item1?.attributes;
 
     return delta..insert('\n', attributes);
   }
@@ -66,19 +66,19 @@ class PreserveBlockStyleOnInsertRule extends InsertRule {
       return null;
     }
 
-    DeltaIterator itr = DeltaIterator(document);
+    final itr = DeltaIterator(document);
     itr.skip(index);
 
-    Tuple2<Operation?, int?> nextNewLine = _getNextNewLine(itr);
-    Style lineStyle =
+    final nextNewLine = _getNextNewLine(itr);
+    final lineStyle =
         Style.fromJson(nextNewLine.item1?.attributes ?? <String, dynamic>{});
 
-    Attribute? attribute = lineStyle.getBlockExceptHeader();
+    final attribute = lineStyle.getBlockExceptHeader();
     if (attribute == null) {
       return null;
     }
 
-    var blockStyle = <String, dynamic>{attribute.key: attribute.value};
+    final blockStyle = <String, dynamic>{attribute.key: attribute.value};
 
     Map<String, dynamic>? resetStyle;
 
@@ -86,10 +86,10 @@ class PreserveBlockStyleOnInsertRule extends InsertRule {
       resetStyle = Attribute.header.toJson();
     }
 
-    List<String> lines = data.split('\n');
-    Delta delta = Delta()..retain(index);
-    for (int i = 0; i < lines.length; i++) {
-      String line = lines[i];
+    final lines = data.split('\n');
+    final delta = Delta()..retain(index);
+    for (var i = 0; i < lines.length; i++) {
+      final line = lines[i];
       if (line.isNotEmpty) {
         delta.insert(line);
       }
@@ -131,10 +131,9 @@ class AutoExitBlockRule extends InsertRule {
       return null;
     }
 
-    DeltaIterator itr = DeltaIterator(document);
-    Operation? prev = itr.skip(index), cur = itr.next();
-    Attribute? blockStyle =
-        Style.fromJson(cur.attributes).getBlockExceptHeader();
+    final itr = DeltaIterator(document);
+    final prev = itr.skip(index), cur = itr.next();
+    final blockStyle = Style.fromJson(cur.attributes).getBlockExceptHeader();
     if (cur.isPlain || blockStyle == null) {
       return null;
     }
@@ -146,7 +145,7 @@ class AutoExitBlockRule extends InsertRule {
       return null;
     }
 
-    Tuple2<Operation?, int?> nextNewLine = _getNextNewLine(itr);
+    final nextNewLine = _getNextNewLine(itr);
     if (nextNewLine.item1 != null &&
         nextNewLine.item1!.attributes != null &&
         Style.fromJson(nextNewLine.item1!.attributes).getBlockExceptHeader() ==
@@ -155,7 +154,7 @@ class AutoExitBlockRule extends InsertRule {
     }
 
     final attributes = cur.attributes ?? <String, dynamic>{};
-    String k = attributes.keys
+    final k = attributes.keys
         .firstWhere((k) => Attribute.blockKeysExceptHeader.contains(k));
     attributes[k] = null;
     // retain(1) should be '\n', set it with no attribute
@@ -173,9 +172,9 @@ class ResetLineFormatOnNewLineRule extends InsertRule {
       return null;
     }
 
-    DeltaIterator itr = DeltaIterator(document);
+    final itr = DeltaIterator(document);
     itr.skip(index);
-    Operation cur = itr.next();
+    final cur = itr.next();
     if (cur.data is! String || !(cur.data as String).startsWith('\n')) {
       return null;
     }
@@ -203,12 +202,12 @@ class InsertEmbedsRule extends InsertRule {
       return null;
     }
 
-    Delta delta = Delta()..retain(index);
-    DeltaIterator itr = DeltaIterator(document);
-    Operation? prev = itr.skip(index), cur = itr.next();
+    final delta = Delta()..retain(index);
+    final itr = DeltaIterator(document);
+    final prev = itr.skip(index), cur = itr.next();
 
-    String? textBefore = prev?.data is String ? prev!.data as String? : '';
-    String textAfter = cur.data is String ? (cur.data as String?)! : '';
+    final textBefore = prev?.data is String ? prev!.data as String? : '';
+    final textAfter = cur.data is String ? (cur.data as String?)! : '';
 
     final isNewlineBefore = prev == null || textBefore!.endsWith('\n');
     final isNewlineAfter = textAfter.startsWith('\n');
@@ -222,7 +221,7 @@ class InsertEmbedsRule extends InsertRule {
       lineStyle = cur.attributes;
     } else {
       while (itr.hasNext) {
-        Operation op = itr.next();
+        final op = itr.next();
         if ((op.data is String ? op.data as String? : '')!.contains('\n')) {
           lineStyle = op.attributes;
           break;
@@ -251,17 +250,17 @@ class ForceNewlineForInsertsAroundEmbedRule extends InsertRule {
       return null;
     }
 
-    String text = data;
-    DeltaIterator itr = DeltaIterator(document);
+    final text = data;
+    final itr = DeltaIterator(document);
     final prev = itr.skip(index);
     final cur = itr.next();
-    bool cursorBeforeEmbed = cur.data is! String;
-    bool cursorAfterEmbed = prev != null && prev.data is! String;
+    final cursorBeforeEmbed = cur.data is! String;
+    final cursorAfterEmbed = prev != null && prev.data is! String;
 
     if (!cursorBeforeEmbed && !cursorAfterEmbed) {
       return null;
     }
-    Delta delta = Delta()..retain(index);
+    final delta = Delta()..retain(index);
     if (cursorBeforeEmbed && !text.endsWith('\n')) {
       return delta..insert(text)..insert('\n');
     }
@@ -282,19 +281,19 @@ class AutoFormatLinksRule extends InsertRule {
       return null;
     }
 
-    DeltaIterator itr = DeltaIterator(document);
-    Operation? prev = itr.skip(index);
+    final itr = DeltaIterator(document);
+    final prev = itr.skip(index);
     if (prev == null || prev.data is! String) {
       return null;
     }
 
     try {
-      String cand = (prev.data as String).split('\n').last.split(' ').last;
-      Uri link = Uri.parse(cand);
+      final cand = (prev.data as String).split('\n').last.split(' ').last;
+      final link = Uri.parse(cand);
       if (!['https', 'http'].contains(link.scheme)) {
         return null;
       }
-      Map<String, dynamic> attributes = prev.attributes ?? <String, dynamic>{};
+      final attributes = prev.attributes ?? <String, dynamic>{};
 
       if (attributes.containsKey(Attribute.link.key)) {
         return null;
@@ -321,16 +320,16 @@ class PreserveInlineStylesRule extends InsertRule {
       return null;
     }
 
-    DeltaIterator itr = DeltaIterator(document);
-    Operation? prev = itr.skip(index);
+    final itr = DeltaIterator(document);
+    final prev = itr.skip(index);
     if (prev == null ||
         prev.data is! String ||
         (prev.data as String).contains('\n')) {
       return null;
     }
 
-    Map<String, dynamic>? attributes = prev.attributes;
-    String text = data;
+    final attributes = prev.attributes;
+    final text = data;
     if (attributes == null || !attributes.containsKey(Attribute.link.key)) {
       return Delta()
         ..retain(index)
@@ -338,13 +337,12 @@ class PreserveInlineStylesRule extends InsertRule {
     }
 
     attributes.remove(Attribute.link.key);
-    Delta delta = Delta()
+    final delta = Delta()
       ..retain(index)
       ..insert(text, attributes.isEmpty ? null : attributes);
-    Operation next = itr.next();
+    final next = itr.next();
 
-    Map<String, dynamic> nextAttributes =
-        next.attributes ?? const <String, dynamic>{};
+    final nextAttributes = next.attributes ?? const <String, dynamic>{};
     if (!nextAttributes.containsKey(Attribute.link.key)) {
       return delta;
     }
@@ -371,9 +369,9 @@ class CatchAllInsertRule extends InsertRule {
 
 Tuple2<Operation?, int?> _getNextNewLine(DeltaIterator iterator) {
   Operation op;
-  for (int skipped = 0; iterator.hasNext; skipped += op.length!) {
+  for (var skipped = 0; iterator.hasNext; skipped += op.length!) {
     op = iterator.next();
-    int lineBreak =
+    final lineBreak =
         (op.data is String ? op.data as String? : '')!.indexOf('\n');
     if (lineBreak >= 0) {
       return Tuple2(op, skipped);

lib/models/rules/rule.dart

@@ -52,7 +52,7 @@ class Rules {
   Delta apply(RuleType ruleType, Document document, int index,
       {int? len, Object? data, Attribute? attribute}) {
     final delta = document.toDelta();
-    for (var rule in _rules) {
+    for (final rule in _rules) {
       if (rule.type != ruleType) {
         continue;
       }

lib/utils/color.dart

@@ -118,8 +118,8 @@ Color stringToColor(String? s) {
     throw 'Color code not supported';
   }
 
-  String hex = s.replaceFirst('#', '');
+  var hex = s.replaceFirst('#', '');
   hex = hex.length == 6 ? 'ff' + hex : hex;
-  int val = int.parse(hex, radix: 16);
+  final val = int.parse(hex, radix: 16);
   return Color(val);
 }

lib/utils/diff_delta.dart

@@ -52,17 +52,17 @@ class Diff {
 
 /* Get diff operation between old text and new text */
 Diff getDiff(String oldText, String newText, int cursorPosition) {
-  int end = oldText.length;
-  int delta = newText.length - end;
-  for (int limit = math.max(0, cursorPosition - delta);
+  var end = oldText.length;
+  final delta = newText.length - end;
+  for (final limit = math.max(0, cursorPosition - delta);
       end > limit && oldText[end - 1] == newText[end + delta - 1];
       end--) {}
-  int start = 0;
-  for (int startLimit = cursorPosition - math.max(0, delta);
+  var start = 0;
+  for (final startLimit = cursorPosition - math.max(0, delta);
       start < startLimit && oldText[start] == newText[start];
       start++) {}
-  String deleted = (start >= end) ? '' : oldText.substring(start, end);
-  String inserted = newText.substring(start, end + delta);
+  final deleted = (start >= end) ? '' : oldText.substring(start, end);
+  final inserted = newText.substring(start, end + delta);
   return Diff(start, deleted, inserted);
 }
 
@@ -71,13 +71,13 @@ int getPositionDelta(Delta user, Delta actual) {
     return 0;
   }
 
-  DeltaIterator userItr = DeltaIterator(user);
-  DeltaIterator actualItr = DeltaIterator(actual);
-  int diff = 0;
+  final userItr = DeltaIterator(user);
+  final actualItr = DeltaIterator(actual);
+  var diff = 0;
   while (userItr.hasNext || actualItr.hasNext) {
     final length = math.min(userItr.peekLength(), actualItr.peekLength());
-    Operation userOperation = userItr.next(length as int);
-    Operation actualOperation = actualItr.next(length);
+    final userOperation = userItr.next(length as int);
+    final actualOperation = actualItr.next(length);
     if (userOperation.length != actualOperation.length) {
       throw 'userOp ' +
           userOperation.length.toString() +

lib/widgets/controller.dart

@@ -43,7 +43,7 @@ class QuillController extends ChangeNotifier {
   }
 
   void undo() {
-    Tuple2 tup = document.undo();
+    final tup = document.undo();
     if (tup.item1) {
       _handleHistoryChange(tup.item2);
     }
@@ -65,7 +65,7 @@ class QuillController extends ChangeNotifier {
   }
 
   void redo() {
-    Tuple2 tup = document.redo();
+    final tup = document.redo();
     if (tup.item1) {
       _handleHistoryChange(tup.item2);
     }
@@ -82,7 +82,7 @@ class QuillController extends ChangeNotifier {
     Delta? delta;
     if (len > 0 || data is! String || data.isNotEmpty) {
       delta = document.replace(index, len, data);
-      bool shouldRetainDelta = toggledStyle.isNotEmpty &&
+      var shouldRetainDelta = toggledStyle.isNotEmpty &&
           delta.isNotEmpty &&
           delta.length <= 2 &&
           delta.last.isInsert;
@@ -98,7 +98,7 @@ class QuillController extends ChangeNotifier {
         }
       }
       if (shouldRetainDelta) {
-        Delta retainDelta = Delta()
+        final retainDelta = Delta()
           ..retain(index)
           ..retain(data is String ? data.length : 1, toggledStyle.toJson());
         document.compose(retainDelta, ChangeSource.LOCAL);
@@ -110,11 +110,11 @@ class QuillController extends ChangeNotifier {
       if (delta == null || delta.isEmpty) {
         _updateSelection(textSelection, ChangeSource.LOCAL);
       } else {
-        Delta user = Delta()
+        final user = Delta()
           ..retain(index)
           ..insert(data)
           ..delete(len);
-        int positionDelta = getPositionDelta(user, delta);
+        final positionDelta = getPositionDelta(user, delta);
         _updateSelection(
           textSelection.copyWith(
             baseOffset: textSelection.baseOffset + positionDelta,
@@ -134,8 +134,8 @@ class QuillController extends ChangeNotifier {
       toggledStyle = toggledStyle.put(attribute);
     }
 
-    Delta change = document.format(index, len, attribute);
-    TextSelection adjustedSelection = selection.copyWith(
+    final change = document.format(index, len, attribute);
+    final adjustedSelection = selection.copyWith(
         baseOffset: change.transformPosition(selection.baseOffset),
         extentOffset: change.transformPosition(selection.extentOffset));
     if (selection != adjustedSelection) {
@@ -177,7 +177,7 @@ class QuillController extends ChangeNotifier {
 
   void _updateSelection(TextSelection textSelection, ChangeSource source) {
     selection = textSelection;
-    int end = document.length - 1;
+    final end = document.length - 1;
     selection = selection.copyWith(
         baseOffset: math.min(selection.baseOffset, end),
         extentOffset: math.min(selection.extentOffset, end));

lib/widgets/cursor.dart

@@ -99,7 +99,7 @@ class CursorCont extends ChangeNotifier {
 
   void _cursorTick(Timer timer) {
     _targetCursorVisibility = !_targetCursorVisibility;
-    double targetOpacity = _targetCursorVisibility ? 1.0 : 0.0;
+    final targetOpacity = _targetCursorVisibility ? 1.0 : 0.0;
     if (style.opacityAnimates) {
       _blinkOpacityCont.animateTo(targetOpacity, curve: Curves.easeOut);
     } else {
@@ -168,9 +168,9 @@ class CursorPainter {
   void paint(Canvas canvas, Offset offset, TextPosition position) {
     assert(prototype != null);
 
-    Offset caretOffset =
+    final caretOffset =
         editable!.getOffsetForCaret(position, prototype) + offset;
-    Rect caretRect = prototype!.shift(caretOffset);
+    var caretRect = prototype!.shift(caretOffset);
     if (style.offset != null) {
       caretRect = caretRect.shift(style.offset!);
     }
@@ -179,7 +179,7 @@ class CursorPainter {
       caretRect = caretRect.shift(Offset(-caretRect.left, 0.0));
     }
 
-    double? caretHeight = editable!.getFullHeightForCaret(position);
+    final caretHeight = editable!.getFullHeightForCaret(position);
     if (caretHeight != null) {
       switch (defaultTargetPlatform) {
         case TargetPlatform.android:
@@ -207,8 +207,8 @@ class CursorPainter {
       }
     }
 
-    Offset caretPosition = editable!.localToGlobal(caretRect.topLeft);
-    double pixelMultiple = 1.0 / devicePixelRatio;
+    final caretPosition = editable!.localToGlobal(caretRect.topLeft);
+    final pixelMultiple = 1.0 / devicePixelRatio;
     caretRect = caretRect.shift(Offset(
         caretPosition.dx.isFinite
             ? (caretPosition.dx / pixelMultiple).round() * pixelMultiple -
@@ -219,13 +219,13 @@ class CursorPainter {
                 caretPosition.dy
             : caretPosition.dy));
 
-    Paint paint = Paint()..color = color;
+    final paint = Paint()..color = color;
     if (style.radius == null) {
       canvas.drawRect(caretRect, paint);
       return;
     }
 
-    RRect caretRRect = RRect.fromRectAndRadius(caretRect, style.radius!);
+    final caretRRect = RRect.fromRectAndRadius(caretRect, style.radius!);
     canvas.drawRRect(caretRRect, paint);
   }
 }

lib/widgets/default_styles.dart

@@ -17,7 +17,7 @@ class QuillStyles extends InheritedWidget {
   }
 
   static DefaultStyles? getStyles(BuildContext context, bool nullOk) {
-    var widget = context.dependOnInheritedWidgetOfExactType<QuillStyles>();
+    final widget = context.dependOnInheritedWidgetOfExactType<QuillStyles>();
     if (widget == null && nullOk) {
       return null;
     }
@@ -84,13 +84,13 @@ class DefaultStyles {
       this.sizeHuge});
 
   static DefaultStyles getInstance(BuildContext context) {
-    ThemeData themeData = Theme.of(context);
-    DefaultTextStyle defaultTextStyle = DefaultTextStyle.of(context);
-    TextStyle baseStyle = defaultTextStyle.style.copyWith(
+    final themeData = Theme.of(context);
+    final defaultTextStyle = DefaultTextStyle.of(context);
+    final baseStyle = defaultTextStyle.style.copyWith(
       fontSize: 16.0,
       height: 1.3,
     );
-    Tuple2<double, double> baseSpacing = const Tuple2(6.0, 0);
+    final baseSpacing = const Tuple2<double, double>(6.0, 0);
     String fontFamily;
     switch (themeData.platform) {
       case TargetPlatform.iOS:

lib/widgets/delegate.dart

@@ -34,7 +34,7 @@ class EditorTextSelectionGestureDetectorBuilder {
   void onTapDown(TapDownDetails details) {
     getRenderEditor()!.handleTapDown(details);
 
-    PointerDeviceKind? kind = details.kind;
+    final kind = details.kind;
     shouldShowSelectionToolbar = kind == null ||
         kind == PointerDeviceKind.touch ||
         kind == PointerDeviceKind.stylus;

lib/widgets/editor.dart

@@ -17,7 +17,6 @@ import '../models/documents/nodes/container.dart' as container_node;
 import '../models/documents/nodes/embed.dart';
 import '../models/documents/nodes/leaf.dart' as leaf;
 import '../models/documents/nodes/line.dart';
-import '../models/documents/nodes/node.dart';
 import 'box.dart';
 import 'controller.dart';
 import 'cursor.dart';
@@ -100,7 +99,7 @@ Widget _defaultEmbedBuilder(BuildContext context, leaf.Embed node) {
   assert(!kIsWeb, 'Please provide EmbedBuilder for Web');
   switch (node.value.type) {
     case 'image':
-      String imageUrl = _standardizeImageUrl(node.value.data);
+      final imageUrl = _standardizeImageUrl(node.value.data);
       return imageUrl.startsWith('http')
           ? Image.network(imageUrl)
           : isBase64(imageUrl)
@@ -188,8 +187,8 @@ class _QuillEditorState extends State<QuillEditor>
 
   @override
   Widget build(BuildContext context) {
-    ThemeData theme = Theme.of(context);
-    TextSelectionThemeData selectionTheme = TextSelectionTheme.of(context);
+    final theme = Theme.of(context);
+    final selectionTheme = TextSelectionTheme.of(context);
 
     TextSelectionControls textSelectionControls;
     bool paintCursorAboveText;
@@ -213,7 +212,7 @@ class _QuillEditorState extends State<QuillEditor>
         break;
       case TargetPlatform.iOS:
       case TargetPlatform.macOS:
-        CupertinoThemeData cupertinoTheme = CupertinoTheme.of(context);
+        final cupertinoTheme = CupertinoTheme.of(context);
         textSelectionControls = cupertinoTextSelectionControls;
         paintCursorAboveText = true;
         cursorOpacityAnimates = true;
@@ -344,16 +343,14 @@ class _QuillEditorSelectionGestureDetectorBuilder
     if (_state.widget.controller.document.isEmpty()) {
       return false;
     }
-    TextPosition pos =
-        getRenderEditor()!.getPositionForOffset(details.globalPosition);
-    container_node.ChildQuery result =
+    final pos = getRenderEditor()!.getPositionForOffset(details.globalPosition);
+    final result =
         getEditor()!.widget.controller.document.queryChild(pos.offset);
     if (result.node == null) {
       return false;
     }
-    Line line = result.node as Line;
-    container_node.ChildQuery segmentResult =
-        line.queryChild(result.offset, false);
+    final line = result.node as Line;
+    final segmentResult = line.queryChild(result.offset, false);
     if (segmentResult.node == null) {
       if (line.length == 1) {
         // tapping when no text yet on this line
@@ -364,7 +361,7 @@ class _QuillEditorSelectionGestureDetectorBuilder
       }
       return false;
     }
-    leaf.Leaf segment = segmentResult.node as leaf.Leaf;
+    final segment = segmentResult.node as leaf.Leaf;
     if (segment.style.containsKey(Attribute.link.key)) {
       var launchUrl = getEditor()!.widget.onLaunchUrl;
       launchUrl ??= _launchUrl;
@@ -380,9 +377,9 @@ class _QuillEditorSelectionGestureDetectorBuilder
       return false;
     }
     if (getEditor()!.widget.readOnly && segment.value is BlockEmbed) {
-      BlockEmbed blockEmbed = segment.value as BlockEmbed;
+      final blockEmbed = segment.value as BlockEmbed;
       if (blockEmbed.type == 'image') {
-        final String imageUrl = _standardizeImageUrl(blockEmbed.data);
+        final imageUrl = _standardizeImageUrl(blockEmbed.data);
         Navigator.push(
           getEditor()!.context,
           MaterialPageRoute(
@@ -413,7 +410,7 @@ class _QuillEditorSelectionGestureDetectorBuilder
       return false;
     }
     // segmentResult.offset == 0 means tap at the beginning of the TextLine
-    String? listVal = line.style.attributes[Attribute.list.key]!.value;
+    final String? listVal = line.style.attributes[Attribute.list.key]!.value;
     if (listVal == Attribute.unchecked.value) {
       getEditor()!
           .widget
@@ -438,7 +435,7 @@ class _QuillEditorSelectionGestureDetectorBuilder
   void onSingleTapUp(TapUpDetails details) {
     getEditor()!.hideToolbar();
 
-    bool positionSelected = _onTapping(details);
+    final positionSelected = _onTapping(details);
 
     if (delegate.getSelectionEnabled() && !positionSelected) {
       switch (Theme.of(_state.context).platform) {
@@ -575,12 +572,12 @@ class RenderEditor extends RenderEditableContainerBox
   List<TextSelectionPoint> getEndpointsForSelection(
       TextSelection textSelection) {
     if (textSelection.isCollapsed) {
-      RenderEditableBox child = childAtPosition(textSelection.extent);
-      TextPosition localPosition = TextPosition(
+      final child = childAtPosition(textSelection.extent);
+      final localPosition = TextPosition(
           offset:
               textSelection.extentOffset - child.getContainer().getOffset());
-      Offset localOffset = child.getOffsetForCaret(localPosition);
-      BoxParentData parentData = child.parentData as BoxParentData;
+      final localOffset = child.getOffsetForCaret(localPosition);
+      final parentData = child.parentData as BoxParentData;
       return <TextSelectionPoint>[
         TextSelectionPoint(
             Offset(0.0, child.preferredLineHeight(localPosition)) +
@@ -590,7 +587,7 @@ class RenderEditor extends RenderEditableContainerBox
       ];
     }
 
-    Node? baseNode = _container.queryChild(textSelection.start, false).node;
+    final baseNode = _container.queryChild(textSelection.start, false).node;
 
     var baseChild = firstChild;
     while (baseChild != null) {
@@ -601,15 +598,14 @@ class RenderEditor extends RenderEditableContainerBox
     }
     assert(baseChild != null);
 
-    BoxParentData baseParentData = baseChild!.parentData as BoxParentData;
-    TextSelection baseSelection =
+    final baseParentData = baseChild!.parentData as BoxParentData;
+    final baseSelection =
         localSelection(baseChild.getContainer(), textSelection, true);
-    TextSelectionPoint basePoint =
-        baseChild.getBaseEndpointForSelection(baseSelection);
+    var basePoint = baseChild.getBaseEndpointForSelection(baseSelection);
     basePoint = TextSelectionPoint(
         basePoint.point + baseParentData.offset, basePoint.direction);
 
-    Node? extentNode = _container.queryChild(textSelection.end, false).node;
+    final extentNode = _container.queryChild(textSelection.end, false).node;
     RenderEditableBox? extentChild = baseChild;
     while (extentChild != null) {
       if (extentChild.getContainer() == extentNode) {
@@ -619,10 +615,10 @@ class RenderEditor extends RenderEditableContainerBox
     }
     assert(extentChild != null);
 
-    BoxParentData extentParentData = extentChild!.parentData as BoxParentData;
-    TextSelection extentSelection =
+    final extentParentData = extentChild!.parentData as BoxParentData;
+    final extentSelection =
         localSelection(extentChild.getContainer(), textSelection, true);
-    TextSelectionPoint extentPoint =
+    var extentPoint =
         extentChild.getExtentEndpointForSelection(extentSelection);
     extentPoint = TextSelectionPoint(
         extentPoint.point + extentParentData.offset, extentPoint.direction);
@@ -643,9 +639,9 @@ class RenderEditor extends RenderEditableContainerBox
     Offset? to,
     SelectionChangedCause cause,
   ) {
-    TextPosition firstPosition = getPositionForOffset(from);
-    TextSelection firstWord = selectWordAtPosition(firstPosition);
-    TextSelection lastWord =
+    final firstPosition = getPositionForOffset(from);
+    final firstWord = selectWordAtPosition(firstPosition);
+    final lastWord =
         to == null ? firstWord : selectWordAtPosition(getPositionForOffset(to));
 
     _handleSelectionChange(
@@ -662,7 +658,7 @@ class RenderEditor extends RenderEditableContainerBox
     TextSelection nextSelection,
     SelectionChangedCause cause,
   ) {
-    bool focusingEmpty = nextSelection.baseOffset == 0 &&
+    final focusingEmpty = nextSelection.baseOffset == 0 &&
         nextSelection.extentOffset == 0 &&
         !_hasFocus;
     if (nextSelection == selection &&
@@ -676,15 +672,15 @@ class RenderEditor extends RenderEditableContainerBox
   @override
   void selectWordEdge(SelectionChangedCause cause) {
     assert(_lastTapDownPosition != null);
-    TextPosition position = getPositionForOffset(_lastTapDownPosition!);
-    RenderEditableBox child = childAtPosition(position);
-    int nodeOffset = child.getContainer().getOffset();
-    TextPosition localPosition = TextPosition(
+    final position = getPositionForOffset(_lastTapDownPosition!);
+    final child = childAtPosition(position);
+    final nodeOffset = child.getContainer().getOffset();
+    final localPosition = TextPosition(
       offset: position.offset - nodeOffset,
       affinity: position.affinity,
     );
-    TextRange localWord = child.getWordBoundary(localPosition);
-    TextRange word = TextRange(
+    final localWord = child.getWordBoundary(localPosition);
+    final word = TextRange(
       start: localWord.start + nodeOffset,
       end: localWord.end + nodeOffset,
     );
@@ -708,17 +704,17 @@ class RenderEditor extends RenderEditableContainerBox
     Offset? to,
     SelectionChangedCause cause,
   ) {
-    TextPosition fromPosition = getPositionForOffset(from);
-    TextPosition? toPosition = to == null ? null : getPositionForOffset(to);
+    final fromPosition = getPositionForOffset(from);
+    final toPosition = to == null ? null : getPositionForOffset(to);
 
-    int baseOffset = fromPosition.offset;
-    int extentOffset = fromPosition.offset;
+    var baseOffset = fromPosition.offset;
+    var extentOffset = fromPosition.offset;
     if (toPosition != null) {
       baseOffset = math.min(fromPosition.offset, toPosition.offset);
       extentOffset = math.max(fromPosition.offset, toPosition.offset);
     }
 
-    TextSelection newSelection = TextSelection(
+    final newSelection = TextSelection(
       baseOffset: baseOffset,
       extentOffset: extentOffset,
       affinity: fromPosition.affinity,
@@ -738,12 +734,12 @@ class RenderEditor extends RenderEditableContainerBox
 
   @override
   TextSelection selectWordAtPosition(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
-    int nodeOffset = child.getContainer().getOffset();
-    TextPosition localPosition = TextPosition(
+    final child = childAtPosition(position);
+    final nodeOffset = child.getContainer().getOffset();
+    final localPosition = TextPosition(
         offset: position.offset - nodeOffset, affinity: position.affinity);
-    TextRange localWord = child.getWordBoundary(localPosition);
-    TextRange word = TextRange(
+    final localWord = child.getWordBoundary(localPosition);
+    final word = TextRange(
       start: localWord.start + nodeOffset,
       end: localWord.end + nodeOffset,
     );
@@ -755,12 +751,12 @@ class RenderEditor extends RenderEditableContainerBox
 
   @override
   TextSelection selectLineAtPosition(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
-    int nodeOffset = child.getContainer().getOffset();
-    TextPosition localPosition = TextPosition(
+    final child = childAtPosition(position);
+    final nodeOffset = child.getContainer().getOffset();
+    final localPosition = TextPosition(
         offset: position.offset - nodeOffset, affinity: position.affinity);
-    TextRange localLineRange = child.getLineBoundary(localPosition);
-    TextRange line = TextRange(
+    final localLineRange = child.getLineBoundary(localPosition);
+    final line = TextRange(
       start: localLineRange.start + nodeOffset,
       end: localLineRange.end + nodeOffset,
     );
@@ -810,19 +806,19 @@ class RenderEditor extends RenderEditableContainerBox
 
   @override
   double preferredLineHeight(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
+    final child = childAtPosition(position);
     return child.preferredLineHeight(TextPosition(
         offset: position.offset - child.getContainer().getOffset()));
   }
 
   @override
   TextPosition getPositionForOffset(Offset offset) {
-    Offset local = globalToLocal(offset);
-    RenderEditableBox child = childAtOffset(local)!;
+    final local = globalToLocal(offset);
+    final child = childAtOffset(local)!;
 
-    BoxParentData parentData = child.parentData as BoxParentData;
-    Offset localOffset = local - parentData.offset;
-    TextPosition localPosition = child.getPositionForOffset(localOffset);
+    final parentData = child.parentData as BoxParentData;
+    final localOffset = local - parentData.offset;
+    final localPosition = child.getPositionForOffset(localOffset);
     return TextPosition(
       offset: localPosition.offset + child.getContainer().getOffset(),
       affinity: localPosition.affinity,
@@ -836,12 +832,12 @@ class RenderEditor extends RenderEditableContainerBox
   /// Returns null if [selection] is already visible.
   double? getOffsetToRevealCursor(
       double viewportHeight, double scrollOffset, double offsetInViewport) {
-    List<TextSelectionPoint> endpoints = getEndpointsForSelection(selection);
-    TextSelectionPoint endpoint = endpoints.first;
-    RenderEditableBox child = childAtPosition(selection.extent);
+    final endpoints = getEndpointsForSelection(selection);
+    final endpoint = endpoints.first;
+    final child = childAtPosition(selection.extent);
     const kMargin = 8.0;
 
-    double caretTop = endpoint.point.dy -
+    final caretTop = endpoint.point.dy -
         child.preferredLineHeight(TextPosition(
             offset:
                 selection.extentOffset - child.getContainer().getOffset())) -
@@ -919,7 +915,7 @@ class RenderEditableContainerBox extends RenderBox
   RenderEditableBox childAtPosition(TextPosition position) {
     assert(firstChild != null);
 
-    Node? targetNode = _container.queryChild(position.offset, false).node;
+    final targetNode = _container.queryChild(position.offset, false).node;
 
     var targetChild = firstChild;
     while (targetChild != null) {
@@ -951,7 +947,8 @@ class RenderEditableContainerBox extends RenderBox
     }
 
     var child = firstChild;
-    double dx = -offset.dx, dy = _resolvedPadding!.top;
+    final dx = -offset.dx;
+    var dy = _resolvedPadding!.top;
     while (child != null) {
       if (child.size.contains(offset.translate(dx, -dy))) {
         return child;
@@ -978,15 +975,14 @@ class RenderEditableContainerBox extends RenderBox
     _resolvePadding();
     assert(_resolvedPadding != null);
 
-    double mainAxisExtent = _resolvedPadding!.top;
+    var mainAxisExtent = _resolvedPadding!.top;
     var child = firstChild;
-    BoxConstraints innerConstraints =
+    final innerConstraints =
         BoxConstraints.tightFor(width: constraints.maxWidth)
             .deflate(_resolvedPadding!);
     while (child != null) {
       child.layout(innerConstraints, parentUsesSize: true);
-      final EditableContainerParentData childParentData =
-          child.parentData as EditableContainerParentData;
+      final childParentData = child.parentData as EditableContainerParentData;
       childParentData.offset = Offset(_resolvedPadding!.left, mainAxisExtent);
       mainAxisExtent += child.size.height;
       assert(child.parentData == childParentData);
@@ -999,24 +995,22 @@ class RenderEditableContainerBox extends RenderBox
   }
 
   double _getIntrinsicCrossAxis(double Function(RenderBox child) childSize) {
-    double extent = 0.0;
+    var extent = 0.0;
     var child = firstChild;
     while (child != null) {
       extent = math.max(extent, childSize(child));
-      EditableContainerParentData childParentData =
-          child.parentData as EditableContainerParentData;
+      final childParentData = child.parentData as EditableContainerParentData;
       child = childParentData.nextSibling;
     }
     return extent;
   }
 
   double _getIntrinsicMainAxis(double Function(RenderBox child) childSize) {
-    double extent = 0.0;
+    var extent = 0.0;
     var child = firstChild;
     while (child != null) {
       extent += childSize(child);
-      EditableContainerParentData childParentData =
-          child.parentData as EditableContainerParentData;
+      final childParentData = child.parentData as EditableContainerParentData;
       child = childParentData.nextSibling;
     }
     return extent;
@@ -1026,7 +1020,7 @@ class RenderEditableContainerBox extends RenderBox
   double computeMinIntrinsicWidth(double height) {
     _resolvePadding();
     return _getIntrinsicCrossAxis((RenderBox child) {
-      double childHeight = math.max(
+      final childHeight = math.max(
           0.0, height - _resolvedPadding!.top + _resolvedPadding!.bottom);
       return child.getMinIntrinsicWidth(childHeight) +
           _resolvedPadding!.left +
@@ -1038,7 +1032,7 @@ class RenderEditableContainerBox extends RenderBox
   double computeMaxIntrinsicWidth(double height) {
     _resolvePadding();
     return _getIntrinsicCrossAxis((RenderBox child) {
-      double childHeight = math.max(
+      final childHeight = math.max(
           0.0, height - _resolvedPadding!.top + _resolvedPadding!.bottom);
       return child.getMaxIntrinsicWidth(childHeight) +
           _resolvedPadding!.left +
@@ -1050,7 +1044,7 @@ class RenderEditableContainerBox extends RenderBox
   double computeMinIntrinsicHeight(double width) {
     _resolvePadding();
     return _getIntrinsicMainAxis((RenderBox child) {
-      double childWidth = math.max(
+      final childWidth = math.max(
           0.0, width - _resolvedPadding!.left + _resolvedPadding!.right);
       return child.getMinIntrinsicHeight(childWidth) +
           _resolvedPadding!.top +

lib/widgets/keyboard_listener.dart

@@ -71,10 +71,10 @@ class KeyboardListener {
       return false;
     }
 
-    Set<LogicalKeyboardKey> keysPressed =
+    final keysPressed =
         LogicalKeyboardKey.collapseSynonyms(RawKeyboard.instance.keysPressed);
-    LogicalKeyboardKey key = event.logicalKey;
-    bool isMacOS = event.data is RawKeyEventDataMacOs;
+    final key = event.logicalKey;
+    final isMacOS = event.data is RawKeyEventDataMacOs;
     if (!_nonModifierKeys.contains(key) ||
         keysPressed
                 .difference(isMacOS ? _macOsModifierKeys : _modifierKeys)

lib/widgets/proxy.dart

@@ -91,8 +91,8 @@ class RenderEmbedProxy extends RenderProxyBox implements RenderContentProxyBox {
       ];
     }
 
-    double left = selection.extentOffset == 0 ? 0.0 : size.width;
-    double right = selection.extentOffset == 0 ? 0.0 : size.width;
+    final left = selection.extentOffset == 0 ? 0.0 : size.width;
+    final right = selection.extentOffset == 0 ? 0.0 : size.width;
     return <TextBox>[
       TextBox.fromLTRBD(left, 0.0, right, size.height, TextDirection.ltr)
     ];

lib/widgets/raw_editor.dart

@@ -15,9 +15,7 @@ import '../models/documents/attribute.dart';
 import '../models/documents/document.dart';
 import '../models/documents/nodes/block.dart';
 import '../models/documents/nodes/line.dart';
-import '../models/documents/nodes/node.dart';
 import '../utils/diff_delta.dart';
-import 'box.dart';
 import 'controller.dart';
 import 'cursor.dart';
 import 'default_styles.dart';
@@ -140,7 +138,7 @@ class RawEditorState extends EditorState
   bool get _hasFocus => widget.focusNode.hasFocus;
 
   TextDirection get _textDirection {
-    TextDirection result = Directionality.of(context);
+    final result = Directionality.of(context);
     return result;
   }
 
@@ -153,13 +151,13 @@ class RawEditorState extends EditorState
     if (wordModifier && lineModifier) {
       return;
     }
-    TextSelection selection = widget.controller.selection;
+    final selection = widget.controller.selection;
 
-    TextSelection newSelection = widget.controller.selection;
+    var newSelection = widget.controller.selection;
 
-    String plainText = textEditingValue.text;
+    final plainText = textEditingValue.text;
 
-    bool rightKey = key == LogicalKeyboardKey.arrowRight,
+    final rightKey = key == LogicalKeyboardKey.arrowRight,
         leftKey = key == LogicalKeyboardKey.arrowLeft,
         upKey = key == LogicalKeyboardKey.arrowUp,
         downKey = key == LogicalKeyboardKey.arrowDown;
@@ -184,7 +182,7 @@ class RawEditorState extends EditorState
 
   TextSelection _placeCollapsedSelection(TextSelection selection,
       TextSelection newSelection, bool leftKey, bool rightKey) {
-    int newOffset = newSelection.extentOffset;
+    var newOffset = newSelection.extentOffset;
     if (!selection.isCollapsed) {
       if (leftKey) {
         newOffset = newSelection.baseOffset < newSelection.extentOffset
@@ -206,34 +204,32 @@ class RawEditorState extends EditorState
       TextSelection selection,
       TextSelection newSelection,
       String plainText) {
-    TextPosition originPosition = TextPosition(
+    final originPosition = TextPosition(
         offset: upKey ? selection.baseOffset : selection.extentOffset);
 
-    RenderEditableBox child =
-        getRenderEditor()!.childAtPosition(originPosition);
-    TextPosition localPosition = TextPosition(
+    final child = getRenderEditor()!.childAtPosition(originPosition);
+    final localPosition = TextPosition(
         offset:
             originPosition.offset - child.getContainer().getDocumentOffset());
 
-    TextPosition? position = upKey
+    var position = upKey
         ? child.getPositionAbove(localPosition)
         : child.getPositionBelow(localPosition);
 
     if (position == null) {
-      var sibling = upKey
+      final sibling = upKey
           ? getRenderEditor()!.childBefore(child)
           : getRenderEditor()!.childAfter(child);
       if (sibling == null) {
         position = TextPosition(offset: upKey ? 0 : plainText.length - 1);
       } else {
-        Offset finalOffset = Offset(
+        final finalOffset = Offset(
             child.getOffsetForCaret(localPosition).dx,
             sibling
                 .getOffsetForCaret(TextPosition(
                     offset: upKey ? sibling.getContainer().length - 1 : 0))
                 .dy);
-        TextPosition siblingPosition =
-            sibling.getPositionForOffset(finalOffset);
+        final siblingPosition = sibling.getPositionForOffset(finalOffset);
         position = TextPosition(
             offset: sibling.getContainer().getDocumentOffset() +
                 siblingPosition.offset);
@@ -273,28 +269,28 @@ class RawEditorState extends EditorState
       bool shift) {
     if (wordModifier) {
       if (leftKey) {
-        TextSelection textSelection = getRenderEditor()!.selectWordAtPosition(
+        final textSelection = getRenderEditor()!.selectWordAtPosition(
             TextPosition(
                 offset: _previousCharacter(
                     newSelection.extentOffset, plainText, false)));
         return newSelection.copyWith(extentOffset: textSelection.baseOffset);
       }
-      TextSelection textSelection = getRenderEditor()!.selectWordAtPosition(
+      final textSelection = getRenderEditor()!.selectWordAtPosition(
           TextPosition(
               offset:
                   _nextCharacter(newSelection.extentOffset, plainText, false)));
       return newSelection.copyWith(extentOffset: textSelection.extentOffset);
     } else if (lineModifier) {
       if (leftKey) {
-        TextSelection textSelection = getRenderEditor()!.selectLineAtPosition(
+        final textSelection = getRenderEditor()!.selectLineAtPosition(
             TextPosition(
                 offset: _previousCharacter(
                     newSelection.extentOffset, plainText, false)));
         return newSelection.copyWith(extentOffset: textSelection.baseOffset);
       }
-      int startPoint = newSelection.extentOffset;
+      final startPoint = newSelection.extentOffset;
       if (startPoint < plainText.length) {
-        TextSelection textSelection = getRenderEditor()!
+        final textSelection = getRenderEditor()!
             .selectLineAtPosition(TextPosition(offset: startPoint));
         return newSelection.copyWith(extentOffset: textSelection.extentOffset);
       }
@@ -302,9 +298,9 @@ class RawEditorState extends EditorState
     }
 
     if (rightKey && newSelection.extentOffset < plainText.length) {
-      int nextExtent =
+      final nextExtent =
           _nextCharacter(newSelection.extentOffset, plainText, true);
-      int distance = nextExtent - newSelection.extentOffset;
+      final distance = nextExtent - newSelection.extentOffset;
       newSelection = newSelection.copyWith(extentOffset: nextExtent);
       if (shift) {
         _cursorResetLocation += distance;
@@ -313,9 +309,9 @@ class RawEditorState extends EditorState
     }
 
     if (leftKey && newSelection.extentOffset > 0) {
-      int previousExtent =
+      final previousExtent =
           _previousCharacter(newSelection.extentOffset, plainText, true);
-      int distance = newSelection.extentOffset - previousExtent;
+      final distance = newSelection.extentOffset - previousExtent;
       newSelection = newSelection.copyWith(extentOffset: previousExtent);
       if (shift) {
         _cursorResetLocation -= distance;
@@ -331,8 +327,8 @@ class RawEditorState extends EditorState
       return string.length;
     }
 
-    int count = 0;
-    Characters remain = string.characters.skipWhile((String currentString) {
+    var count = 0;
+    final remain = string.characters.skipWhile((String currentString) {
       if (count <= index) {
         count += currentString.length;
         return true;
@@ -351,9 +347,9 @@ class RawEditorState extends EditorState
       return 0;
     }
 
-    int count = 0;
+    var count = 0;
     int? lastNonWhitespace;
-    for (String currentString in string.characters) {
+    for (final currentString in string.characters) {
       if (!includeWhitespace &&
           !WHITE_SPACE.contains(
               currentString.characters.first.toString().codeUnitAt(0))) {
@@ -411,7 +407,7 @@ class RawEditorState extends EditorState
       return;
     }
 
-    TextEditingValue actualValue = textEditingValue.copyWith(
+    final actualValue = textEditingValue.copyWith(
       composing: _lastKnownRemoteTextEditingValue!.composing,
     );
 
@@ -419,7 +415,7 @@ class RawEditorState extends EditorState
       return;
     }
 
-    bool shouldRemember =
+    final shouldRemember =
         textEditingValue.text != _lastKnownRemoteTextEditingValue!.text;
     _lastKnownRemoteTextEditingValue = actualValue;
     _textInputConnection!.setEditingState(actualValue);
@@ -456,13 +452,12 @@ class RawEditorState extends EditorState
       return;
     }
 
-    TextEditingValue effectiveLastKnownValue =
-        _lastKnownRemoteTextEditingValue!;
+    final effectiveLastKnownValue = _lastKnownRemoteTextEditingValue!;
     _lastKnownRemoteTextEditingValue = value;
-    String oldText = effectiveLastKnownValue.text;
-    String text = value.text;
-    int cursorPosition = value.selection.extentOffset;
-    Diff diff = getDiff(oldText, text, cursorPosition);
+    final oldText = effectiveLastKnownValue.text;
+    final text = value.text;
+    final cursorPosition = value.selection.extentOffset;
+    final diff = getDiff(oldText, text, cursorPosition);
     widget.controller.replaceText(
         diff.start, diff.deleted.length, diff.inserted, value.selection);
   }
@@ -513,7 +508,7 @@ class RawEditorState extends EditorState
     _focusAttachment!.reparent();
     super.build(context);
 
-    Document _doc = widget.controller.document;
+    var _doc = widget.controller.document;
     if (_doc.isEmpty() &&
         !widget.focusNode.hasFocus &&
         widget.placeholder != null) {
@@ -540,7 +535,7 @@ class RawEditorState extends EditorState
     );
 
     if (widget.scrollable) {
-      EdgeInsets baselinePadding =
+      final baselinePadding =
           EdgeInsets.only(top: _styles!.paragraph!.verticalSpacing.item1);
       child = BaselineProxy(
         textStyle: _styles!.paragraph!.style,
@@ -553,7 +548,7 @@ class RawEditorState extends EditorState
       );
     }
 
-    BoxConstraints constraints = widget.expands
+    final constraints = widget.expands
         ? const BoxConstraints.expand()
         : BoxConstraints(
             minHeight: widget.minHeight ?? 0.0,
@@ -584,15 +579,14 @@ class RawEditorState extends EditorState
 
   List<Widget> _buildChildren(Document doc, BuildContext context) {
     final result = <Widget>[];
-    Map<int, int> indentLevelCounts = {};
-    for (Node node in doc.root.children) {
+    final indentLevelCounts = <int, int>{};
+    for (final node in doc.root.children) {
       if (node is Line) {
-        EditableTextLine editableTextLine =
-            _getEditableTextLineFromNode(node, context);
+        final editableTextLine = _getEditableTextLineFromNode(node, context);
         result.add(editableTextLine);
       } else if (node is Block) {
-        Map<String, Attribute> attrs = node.style.attributes;
-        EditableTextBlock editableTextBlock = EditableTextBlock(
+        final attrs = node.style.attributes;
+        final editableTextBlock = EditableTextBlock(
             node,
             _textDirection,
             _getVerticalSpacingForBlock(node, _styles),
@@ -617,13 +611,13 @@ class RawEditorState extends EditorState
 
   EditableTextLine _getEditableTextLineFromNode(
       Line node, BuildContext context) {
-    TextLine textLine = TextLine(
+    final textLine = TextLine(
       line: node,
       textDirection: _textDirection,
       embedBuilder: widget.embedBuilder,
       styles: _styles!,
     );
-    EditableTextLine editableTextLine = EditableTextLine(
+    final editableTextLine = EditableTextLine(
         node,
         null,
         textLine,
@@ -641,9 +635,9 @@ class RawEditorState extends EditorState
 
   Tuple2<double, double> _getVerticalSpacingForLine(
       Line line, DefaultStyles? defaultStyles) {
-    Map<String, Attribute> attrs = line.style.attributes;
+    final attrs = line.style.attributes;
     if (attrs.containsKey(Attribute.header.key)) {
-      int? level = attrs[Attribute.header.key]!.value;
+      final int? level = attrs[Attribute.header.key]!.value;
       switch (level) {
         case 1:
           return defaultStyles!.h1!.verticalSpacing;
@@ -661,7 +655,7 @@ class RawEditorState extends EditorState
 
   Tuple2<double, double> _getVerticalSpacingForBlock(
       Block node, DefaultStyles? defaultStyles) {
-    Map<String, Attribute> attrs = node.style.attributes;
+    final attrs = node.style.attributes;
     if (attrs.containsKey(Attribute.blockQuote.key)) {
       return defaultStyles!.quote!.verticalSpacing;
     } else if (attrs.containsKey(Attribute.codeBlock.key)) {
@@ -720,8 +714,8 @@ class RawEditorState extends EditorState
   @override
   void didChangeDependencies() {
     super.didChangeDependencies();
-    DefaultStyles? parentStyles = QuillStyles.getStyles(context, true);
-    DefaultStyles defaultStyles = DefaultStyles.getInstance(context);
+    final parentStyles = QuillStyles.getStyles(context, true);
+    final defaultStyles = DefaultStyles.getInstance(context);
     _styles = (parentStyles != null)
         ? defaultStyles.merge(parentStyles)
         : defaultStyles;
@@ -784,27 +778,26 @@ class RawEditorState extends EditorState
   }
 
   void handleDelete(bool forward) {
-    TextSelection selection = widget.controller.selection;
-    String plainText = textEditingValue.text;
-    int cursorPosition = selection.start;
-    String textBefore = selection.textBefore(plainText);
-    String textAfter = selection.textAfter(plainText);
+    final selection = widget.controller.selection;
+    final plainText = textEditingValue.text;
+    var cursorPosition = selection.start;
+    var textBefore = selection.textBefore(plainText);
+    var textAfter = selection.textAfter(plainText);
     if (selection.isCollapsed) {
       if (!forward && textBefore.isNotEmpty) {
-        final int characterBoundary =
+        final characterBoundary =
             _previousCharacter(textBefore.length, textBefore, true);
         textBefore = textBefore.substring(0, characterBoundary);
         cursorPosition = characterBoundary;
       }
       if (forward && textAfter.isNotEmpty && textAfter != '\n') {
-        final int deleteCount = _nextCharacter(0, textAfter, true);
+        final deleteCount = _nextCharacter(0, textAfter, true);
         textAfter = textAfter.substring(deleteCount);
       }
     }
-    TextSelection newSelection =
-        TextSelection.collapsed(offset: cursorPosition);
-    String newText = textBefore + textAfter;
-    int size = plainText.length - newText.length;
+    final newSelection = TextSelection.collapsed(offset: cursorPosition);
+    final newText = textBefore + textAfter;
+    final size = plainText.length - newText.length;
     widget.controller.replaceText(
       cursorPosition,
       size,
@@ -814,8 +807,8 @@ class RawEditorState extends EditorState
   }
 
   void handleShortcut(InputShortcut? shortcut) async {
-    TextSelection selection = widget.controller.selection;
-    String plainText = textEditingValue.text;
+    final selection = widget.controller.selection;
+    final plainText = textEditingValue.text;
     if (shortcut == InputShortcut.COPY) {
       if (!selection.isCollapsed) {
         await Clipboard.setData(
@@ -844,7 +837,7 @@ class RawEditorState extends EditorState
       return;
     }
     if (shortcut == InputShortcut.PASTE && !widget.readOnly) {
-      ClipboardData? data = await Clipboard.getData(Clipboard.kTextPlain);
+      final data = await Clipboard.getData(Clipboard.kTextPlain);
       if (data != null) {
         widget.controller.replaceText(
           selection.start,
@@ -1074,8 +1067,8 @@ class RawEditorState extends EditorState
         value.selection,
       );
     } else {
-      final TextEditingValue value = textEditingValue;
-      final ClipboardData? data = await Clipboard.getData(Clipboard.kTextPlain);
+      final value = textEditingValue;
+      final data = await Clipboard.getData(Clipboard.kTextPlain);
       if (data != null) {
         final length =
             textEditingValue.selection.end - textEditingValue.selection.start;
@@ -1095,7 +1088,7 @@ class RawEditorState extends EditorState
   }
 
   Future<bool> __isItCut(TextEditingValue value) async {
-    ClipboardData? data = await Clipboard.getData(Clipboard.kTextPlain);
+    final data = await Clipboard.getData(Clipboard.kTextPlain);
     if (data == null) {
       return false;
     }

lib/widgets/text_block.dart

@@ -6,7 +6,6 @@ import 'package:tuple/tuple.dart';
 import '../models/documents/attribute.dart';
 import '../models/documents/nodes/block.dart';
 import '../models/documents/nodes/line.dart';
-import '../models/documents/nodes/node.dart';
 import 'box.dart';
 import 'cursor.dart';
 import 'default_styles.dart';
@@ -79,7 +78,7 @@ class EditableTextBlock extends StatelessWidget {
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
 
-    DefaultStyles? defaultStyles = QuillStyles.getStyles(context, false);
+    final defaultStyles = QuillStyles.getStyles(context, false);
     return _EditableBlock(
         block,
         textDirection,
@@ -91,7 +90,7 @@ class EditableTextBlock extends StatelessWidget {
 
   BoxDecoration? _getDecorationForBlock(
       Block node, DefaultStyles? defaultStyles) {
-    Map<String, Attribute> attrs = block.style.attributes;
+    final attrs = block.style.attributes;
     if (attrs.containsKey(Attribute.blockQuote.key)) {
       return defaultStyles!.quote!.decoration;
     }
@@ -103,13 +102,13 @@ class EditableTextBlock extends StatelessWidget {
 
   List<Widget> _buildChildren(
       BuildContext context, Map<int, int> indentLevelCounts) {
-    DefaultStyles? defaultStyles = QuillStyles.getStyles(context, false);
-    int count = block.children.length;
-    var children = <Widget>[];
-    int index = 0;
-    for (Line line in Iterable.castFrom<dynamic, Line>(block.children)) {
+    final defaultStyles = QuillStyles.getStyles(context, false);
+    final count = block.children.length;
+    final children = <Widget>[];
+    var index = 0;
+    for (final line in Iterable.castFrom<dynamic, Line>(block.children)) {
       index++;
-      EditableTextLine editableTextLine = EditableTextLine(
+      final editableTextLine = EditableTextLine(
           line,
           _buildLeading(context, line, index, indentLevelCounts, count),
           TextLine(
@@ -134,8 +133,8 @@ class EditableTextBlock extends StatelessWidget {
 
   Widget? _buildLeading(BuildContext context, Line line, int index,
       Map<int, int> indentLevelCounts, int count) {
-    DefaultStyles? defaultStyles = QuillStyles.getStyles(context, false);
-    Map<String, Attribute> attrs = line.style.attributes;
+    final defaultStyles = QuillStyles.getStyles(context, false);
+    final attrs = line.style.attributes;
     if (attrs[Attribute.list.key] == Attribute.ol) {
       return _NumberPoint(
         index: index,
@@ -183,10 +182,10 @@ class EditableTextBlock extends StatelessWidget {
   }
 
   double _getIndentWidth() {
-    Map<String, Attribute> attrs = block.style.attributes;
+    final attrs = block.style.attributes;
 
-    Attribute? indent = attrs[Attribute.indent.key];
-    double extraIndent = 0.0;
+    final indent = attrs[Attribute.indent.key];
+    var extraIndent = 0.0;
     if (indent != null && indent.value != null) {
       extraIndent = 16.0 * indent.value;
     }
@@ -200,11 +199,11 @@ class EditableTextBlock extends StatelessWidget {
 
   Tuple2 _getSpacingForLine(
       Line node, int index, int count, DefaultStyles? defaultStyles) {
-    double top = 0.0, bottom = 0.0;
+    var top = 0.0, bottom = 0.0;
 
-    Map<String, Attribute> attrs = block.style.attributes;
+    final attrs = block.style.attributes;
     if (attrs.containsKey(Attribute.header.key)) {
-      int? level = attrs[Attribute.header.key]!.value;
+      final level = attrs[Attribute.header.key]!.value;
       switch (level) {
         case 1:
           top = defaultStyles!.h1!.verticalSpacing.item1;
@@ -310,8 +309,8 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
 
   @override
   TextRange getLineBoundary(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
-    TextRange rangeInChild = child.getLineBoundary(TextPosition(
+    final child = childAtPosition(position);
+    final rangeInChild = child.getLineBoundary(TextPosition(
       offset: position.offset - child.getContainer().getOffset(),
       affinity: position.affinity,
     ));
@@ -323,7 +322,7 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
 
   @override
   Offset getOffsetForCaret(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
+    final child = childAtPosition(position);
     return child.getOffsetForCaret(TextPosition(
           offset: position.offset - child.getContainer().getOffset(),
           affinity: position.affinity,
@@ -333,9 +332,9 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
 
   @override
   TextPosition getPositionForOffset(Offset offset) {
-    RenderEditableBox child = childAtOffset(offset)!;
-    BoxParentData parentData = child.parentData as BoxParentData;
-    TextPosition localPosition =
+    final child = childAtOffset(offset)!;
+    final parentData = child.parentData as BoxParentData;
+    final localPosition =
         child.getPositionForOffset(offset - parentData.offset);
     return TextPosition(
       offset: localPosition.offset + child.getContainer().getOffset(),
@@ -345,9 +344,9 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
 
   @override
   TextRange getWordBoundary(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
-    int nodeOffset = child.getContainer().getOffset();
-    TextRange childWord = child
+    final child = childAtPosition(position);
+    final nodeOffset = child.getContainer().getOffset();
+    final childWord = child
         .getWordBoundary(TextPosition(offset: position.offset - nodeOffset));
     return TextRange(
       start: childWord.start + nodeOffset,
@@ -359,25 +358,25 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
   TextPosition? getPositionAbove(TextPosition position) {
     assert(position.offset < getContainer().length);
 
-    RenderEditableBox child = childAtPosition(position);
-    TextPosition childLocalPosition = TextPosition(
+    final child = childAtPosition(position);
+    final childLocalPosition = TextPosition(
         offset: position.offset - child.getContainer().getOffset());
-    TextPosition? result = child.getPositionAbove(childLocalPosition);
+    final result = child.getPositionAbove(childLocalPosition);
     if (result != null) {
       return TextPosition(
           offset: result.offset + child.getContainer().getOffset());
     }
 
-    RenderEditableBox? sibling = childBefore(child);
+    final sibling = childBefore(child);
     if (sibling == null) {
       return null;
     }
 
-    Offset caretOffset = child.getOffsetForCaret(childLocalPosition);
-    TextPosition testPosition =
+    final caretOffset = child.getOffsetForCaret(childLocalPosition);
+    final testPosition =
         TextPosition(offset: sibling.getContainer().length - 1);
-    Offset testOffset = sibling.getOffsetForCaret(testPosition);
-    Offset finalOffset = Offset(caretOffset.dx, testOffset.dy);
+    final testOffset = sibling.getOffsetForCaret(testPosition);
+    final finalOffset = Offset(caretOffset.dx, testOffset.dy);
     return TextPosition(
         offset: sibling.getContainer().getOffset() +
             sibling.getPositionForOffset(finalOffset).offset);
@@ -387,24 +386,23 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
   TextPosition? getPositionBelow(TextPosition position) {
     assert(position.offset < getContainer().length);
 
-    RenderEditableBox child = childAtPosition(position);
-    TextPosition childLocalPosition = TextPosition(
+    final child = childAtPosition(position);
+    final childLocalPosition = TextPosition(
         offset: position.offset - child.getContainer().getOffset());
-    TextPosition? result = child.getPositionBelow(childLocalPosition);
+    final result = child.getPositionBelow(childLocalPosition);
     if (result != null) {
       return TextPosition(
           offset: result.offset + child.getContainer().getOffset());
     }
 
-    RenderEditableBox? sibling = childAfter(child);
+    final sibling = childAfter(child);
     if (sibling == null) {
       return null;
     }
 
-    Offset caretOffset = child.getOffsetForCaret(childLocalPosition);
-    Offset testOffset =
-        sibling.getOffsetForCaret(const TextPosition(offset: 0));
-    Offset finalOffset = Offset(caretOffset.dx, testOffset.dy);
+    final caretOffset = child.getOffsetForCaret(childLocalPosition);
+    final testOffset = sibling.getOffsetForCaret(const TextPosition(offset: 0));
+    final finalOffset = Offset(caretOffset.dx, testOffset.dy);
     return TextPosition(
         offset: sibling.getContainer().getOffset() +
             sibling.getPositionForOffset(finalOffset).offset);
@@ -412,7 +410,7 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
 
   @override
   double preferredLineHeight(TextPosition position) {
-    RenderEditableBox child = childAtPosition(position);
+    final child = childAtPosition(position);
     return child.preferredLineHeight(TextPosition(
         offset: position.offset - child.getContainer().getOffset()));
   }
@@ -426,7 +424,7 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
           null);
     }
 
-    Node? baseNode = getContainer().queryChild(selection.start, false).node;
+    final baseNode = getContainer().queryChild(selection.start, false).node;
     var baseChild = firstChild;
     while (baseChild != null) {
       if (baseChild.getContainer() == baseNode) {
@@ -436,7 +434,7 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
     }
     assert(baseChild != null);
 
-    TextSelectionPoint basePoint = baseChild!.getBaseEndpointForSelection(
+    final basePoint = baseChild!.getBaseEndpointForSelection(
         localSelection(baseChild.getContainer(), selection, true));
     return TextSelectionPoint(
         basePoint.point + (baseChild.parentData as BoxParentData).offset,
@@ -452,7 +450,7 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
           null);
     }
 
-    Node? extentNode = getContainer().queryChild(selection.end, false).node;
+    final extentNode = getContainer().queryChild(selection.end, false).node;
 
     var extentChild = firstChild;
     while (extentChild != null) {
@@ -463,7 +461,7 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
     }
     assert(extentChild != null);
 
-    TextSelectionPoint extentPoint = extentChild!.getExtentEndpointForSelection(
+    final extentPoint = extentChild!.getExtentEndpointForSelection(
         localSelection(extentChild.getContainer(), selection, true));
     return TextSelectionPoint(
         extentPoint.point + (extentChild.parentData as BoxParentData).offset,
@@ -487,11 +485,11 @@ class RenderEditableTextBlock extends RenderEditableContainerBox
   void _paintDecoration(PaintingContext context, Offset offset) {
     _painter ??= _decoration.createBoxPainter(markNeedsPaint);
 
-    EdgeInsets decorationPadding = resolvedPadding! - _contentPadding;
+    final decorationPadding = resolvedPadding! - _contentPadding;
 
-    ImageConfiguration filledConfiguration =
+    final filledConfiguration =
         configuration.copyWith(size: decorationPadding.deflateSize(size));
-    int debugSaveCount = context.canvas.getSaveCount();
+    final debugSaveCount = context.canvas.getSaveCount();
 
     final decorationOffset =
         offset.translate(decorationPadding.left, decorationPadding.top);
@@ -572,7 +570,7 @@ class _NumberPoint extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    String s = index.toString();
+    var s = index.toString();
     int? level = 0;
     if (!attrs.containsKey(Attribute.indent.key) &&
         !indentLevelCounts.containsKey(1)) {
@@ -595,7 +593,7 @@ class _NumberPoint extends StatelessWidget {
       // last visited level is done, going up
       indentLevelCounts.remove(level + 1);
     }
-    int count = (indentLevelCounts[level] ?? 0) + 1;
+    final count = (indentLevelCounts[level] ?? 0) + 1;
     indentLevelCounts[level] = count;
 
     s = count.toString();

lib/widgets/text_line.dart

@@ -11,7 +11,6 @@ import '../models/documents/nodes/leaf.dart' as leaf;
 import '../models/documents/nodes/leaf.dart';
 import '../models/documents/nodes/line.dart';
 import '../models/documents/nodes/node.dart';
-import '../models/documents/style.dart';
 import '../utils/color.dart';
 import 'box.dart';
 import 'cursor.dart';
@@ -39,14 +38,14 @@ class TextLine extends StatelessWidget {
     assert(debugCheckHasMediaQuery(context));
 
     if (line.hasEmbed) {
-      Embed embed = line.children.single as Embed;
+      final embed = line.children.single as Embed;
       return EmbedProxy(embedBuilder(context, embed));
     }
 
     final textSpan = _buildTextSpan(context);
     final strutStyle = StrutStyle.fromTextStyle(textSpan.style!);
     final textAlign = _getTextAlign();
-    RichText child = RichText(
+    final child = RichText(
       text: textSpan,
       textAlign: textAlign,
       textDirection: textDirection,
@@ -80,20 +79,20 @@ class TextLine extends StatelessWidget {
   }
 
   TextSpan _buildTextSpan(BuildContext context) {
-    DefaultStyles defaultStyles = styles;
-    List<TextSpan> children = line.children
+    final defaultStyles = styles;
+    final children = line.children
         .map((node) => _getTextSpanFromNode(defaultStyles, node))
         .toList(growable: false);
 
-    TextStyle textStyle = const TextStyle();
+    var textStyle = const TextStyle();
 
     if (line.style.containsKey(Attribute.placeholder.key)) {
       textStyle = defaultStyles.placeHolder!.style;
       return TextSpan(children: children, style: textStyle);
     }
 
-    Attribute? header = line.style.attributes[Attribute.header.key];
-    Map<Attribute, TextStyle> m = {
+    final header = line.style.attributes[Attribute.header.key];
+    final m = <Attribute, TextStyle>{
       Attribute.h1: defaultStyles.h1!.style,
       Attribute.h2: defaultStyles.h2!.style,
       Attribute.h3: defaultStyles.h3!.style,
@@ -101,7 +100,7 @@ class TextLine extends StatelessWidget {
 
     textStyle = textStyle.merge(m[header] ?? defaultStyles.paragraph!.style);
 
-    Attribute? block = line.style.getBlockExceptHeader();
+    final block = line.style.getBlockExceptHeader();
     TextStyle? toMerge;
     if (block == Attribute.blockQuote) {
       toMerge = defaultStyles.quote!.style;
@@ -117,11 +116,11 @@ class TextLine extends StatelessWidget {
   }
 
   TextSpan _getTextSpanFromNode(DefaultStyles defaultStyles, Node node) {
-    leaf.Text textNode = node as leaf.Text;
-    Style style = textNode.style;
-    TextStyle res = const TextStyle();
+    final textNode = node as leaf.Text;
+    final style = textNode.style;
+    var res = const TextStyle();
 
-    Map<String, TextStyle?> m = {
+    final m = <String, TextStyle?>{
       Attribute.bold.key: defaultStyles.bold,
       Attribute.italic.key: defaultStyles.italic,
       Attribute.link.key: defaultStyles.link,
@@ -134,12 +133,12 @@ class TextLine extends StatelessWidget {
       }
     });
 
-    Attribute? font = textNode.style.attributes[Attribute.font.key];
+    final font = textNode.style.attributes[Attribute.font.key];
     if (font != null && font.value != null) {
       res = res.merge(TextStyle(fontFamily: font.value));
     }
 
-    Attribute? size = textNode.style.attributes[Attribute.size.key];
+    final size = textNode.style.attributes[Attribute.size.key];
     if (size != null && size.value != null) {
       switch (size.value) {
         case 'small':
@@ -152,7 +151,7 @@ class TextLine extends StatelessWidget {
           res = res.merge(defaultStyles.sizeHuge);
           break;
         default:
-          double? fontSize = double.tryParse(size.value);
+          final fontSize = double.tryParse(size.value);
           if (fontSize != null) {
             res = res.merge(TextStyle(fontSize: fontSize));
           } else {
@@ -161,7 +160,7 @@ class TextLine extends StatelessWidget {
       }
     }
 
-    Attribute? color = textNode.style.attributes[Attribute.color.key];
+    final color = textNode.style.attributes[Attribute.color.key];
     if (color != null && color.value != null) {
       var textColor = defaultStyles.color;
       if (color.value is String) {
@@ -172,7 +171,7 @@ class TextLine extends StatelessWidget {
       }
     }
 
-    Attribute? background = textNode.style.attributes[Attribute.background.key];
+    final background = textNode.style.attributes[Attribute.background.key];
     if (background != null && background.value != null) {
       final backgroundColor = stringToColor(background.value);
       res = res.merge(TextStyle(backgroundColor: backgroundColor));
@@ -345,7 +344,7 @@ class RenderEditableTextLine extends RenderEditableBox {
       return;
     }
 
-    bool containsSelection = containsTextSelection();
+    final containsSelection = containsTextSelection();
     if (attached && containsCursor()) {
       cursorCont.removeListener(markNeedsLayout);
       cursorCont.color.removeListener(markNeedsPaint);
@@ -424,7 +423,7 @@ class RenderEditableTextLine extends RenderEditableBox {
   }
 
   List<TextBox> _getBoxes(TextSelection textSelection) {
-    BoxParentData? parentData = _body!.parentData as BoxParentData?;
+    final parentData = _body!.parentData as BoxParentData?;
     return _body!.getBoxesForSelection(textSelection).map((box) {
       return TextBox.fromLTRBD(
         box.left + parentData!.offset.dx,
@@ -463,9 +462,9 @@ class RenderEditableTextLine extends RenderEditableBox {
               getOffsetForCaret(textSelection.extent),
           null);
     }
-    List<TextBox> boxes = _getBoxes(textSelection);
+    final boxes = _getBoxes(textSelection);
     assert(boxes.isNotEmpty);
-    TextBox targetBox = first ? boxes.first : boxes.last;
+    final targetBox = first ? boxes.first : boxes.last;
     return TextSelectionPoint(
         Offset(first ? targetBox.start : targetBox.end, targetBox.bottom),
         targetBox.direction);
@@ -473,10 +472,10 @@ class RenderEditableTextLine extends RenderEditableBox {
 
   @override
   TextRange getLineBoundary(TextPosition position) {
-    double lineDy = getOffsetForCaret(position)
+    final lineDy = getOffsetForCaret(position)
         .translate(0.0, 0.5 * preferredLineHeight(position))
         .dy;
-    List<TextBox> lineBoxes =
+    final lineBoxes =
         _getBoxes(TextSelection(baseOffset: 0, extentOffset: line.length - 1))
             .where((element) => element.top < lineDy && element.bottom > lineDy)
             .toList(growable: false);
@@ -504,7 +503,7 @@ class RenderEditableTextLine extends RenderEditableBox {
 
   TextPosition? _getPosition(TextPosition textPosition, double dyScale) {
     assert(textPosition.offset < line.length);
-    Offset offset = getOffsetForCaret(textPosition)
+    final offset = getOffsetForCaret(textPosition)
         .translate(0, dyScale * preferredLineHeight(textPosition));
     if (_body!.size
         .contains(offset - (_body!.parentData as BoxParentData).offset)) {
@@ -574,7 +573,7 @@ class RenderEditableTextLine extends RenderEditableBox {
   @override
   void detach() {
     super.detach();
-    for (RenderBox child in _children) {
+    for (final child in _children) {
       child.detach();
     }
     if (containsCursor()) {
@@ -595,7 +594,7 @@ class RenderEditableTextLine extends RenderEditableBox {
 
   @override
   List<DiagnosticsNode> debugDescribeChildren() {
-    var value = <DiagnosticsNode>[];
+    final value = <DiagnosticsNode>[];
     void add(RenderBox? child, String name) {
       if (child != null) {
         value.add(child.toDiagnosticsNode(name: name));
@@ -613,12 +612,12 @@ class RenderEditableTextLine extends RenderEditableBox {
   @override
   double computeMinIntrinsicWidth(double height) {
     _resolvePadding();
-    double horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
-    double verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
-    int leadingWidth = _leading == null
+    final horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
+    final verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
+    final leadingWidth = _leading == null
         ? 0
         : _leading!.getMinIntrinsicWidth(height - verticalPadding) as int;
-    int bodyWidth = _body == null
+    final bodyWidth = _body == null
         ? 0
         : _body!.getMinIntrinsicWidth(math.max(0.0, height - verticalPadding))
             as int;
@@ -628,12 +627,12 @@ class RenderEditableTextLine extends RenderEditableBox {
   @override
   double computeMaxIntrinsicWidth(double height) {
     _resolvePadding();
-    double horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
-    double verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
-    int leadingWidth = _leading == null
+    final horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
+    final verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
+    final leadingWidth = _leading == null
         ? 0
         : _leading!.getMaxIntrinsicWidth(height - verticalPadding) as int;
-    int bodyWidth = _body == null
+    final bodyWidth = _body == null
         ? 0
         : _body!.getMaxIntrinsicWidth(math.max(0.0, height - verticalPadding))
             as int;
@@ -643,8 +642,8 @@ class RenderEditableTextLine extends RenderEditableBox {
   @override
   double computeMinIntrinsicHeight(double width) {
     _resolvePadding();
-    double horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
-    double verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
+    final horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
+    final verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
     if (_body != null) {
       return _body!
               .getMinIntrinsicHeight(math.max(0.0, width - horizontalPadding)) +
@@ -656,8 +655,8 @@ class RenderEditableTextLine extends RenderEditableBox {
   @override
   double computeMaxIntrinsicHeight(double width) {
     _resolvePadding();
-    double horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
-    double verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
+    final horizontalPadding = _resolvedPadding!.left + _resolvedPadding!.right;
+    final verticalPadding = _resolvedPadding!.top + _resolvedPadding!.bottom;
     if (_body != null) {
       return _body!
               .getMaxIntrinsicHeight(math.max(0.0, width - horizontalPadding)) +
@@ -849,8 +848,8 @@ class _TextLineElement extends RenderObjectElement {
   }
 
   void _mountChild(Widget? widget, TextLineSlot slot) {
-    Element? oldChild = _slotToChildren[slot];
-    Element? newChild = updateChild(oldChild, widget, slot);
+    final oldChild = _slotToChildren[slot];
+    final newChild = updateChild(oldChild, widget, slot);
     if (oldChild != null) {
       _slotToChildren.remove(slot);
     }
@@ -873,8 +872,8 @@ class _TextLineElement extends RenderObjectElement {
   }
 
   void _updateChild(Widget? widget, TextLineSlot slot) {
-    Element? oldChild = _slotToChildren[slot];
-    Element? newChild = updateChild(oldChild, widget, slot);
+    final oldChild = _slotToChildren[slot];
+    final newChild = updateChild(oldChild, widget, slot);
     if (oldChild != null) {
       _slotToChildren.remove(slot);
     }

lib/widgets/text_selection.dart

@@ -12,10 +12,10 @@ import '../models/documents/nodes/node.dart';
 import 'editor.dart';
 
 TextSelection localSelection(Node node, TextSelection selection, fromParent) {
-  int base = fromParent ? node.getOffset() : node.getDocumentOffset();
+  final base = fromParent ? node.getOffset() : node.getDocumentOffset();
   assert(base <= selection.end && selection.start <= base + node.length - 1);
 
-  int offset = fromParent ? node.getOffset() : node.getDocumentOffset();
+  final offset = fromParent ? node.getOffset() : node.getDocumentOffset();
   return selection.copyWith(
       baseOffset: math.max(selection.start - offset, 0),
       extentOffset: math.min(selection.end - offset, node.length - 1));
@@ -55,7 +55,7 @@ class EditorTextSelectionOverlay {
       this.dragStartBehavior,
       this.onSelectionHandleTapped,
       this.clipboardStatus) {
-    OverlayState overlay = Overlay.of(context, rootOverlay: true)!;
+    final overlay = Overlay.of(context, rootOverlay: true)!;
 
     _toolbarController = AnimationController(
         duration: const Duration(milliseconds: 150), vsync: overlay);
@@ -161,26 +161,25 @@ class EditorTextSelectionOverlay {
   }
 
   Widget _buildToolbar(BuildContext context) {
-    List<TextSelectionPoint> endpoints =
-        renderObject!.getEndpointsForSelection(_selection);
+    final endpoints = renderObject!.getEndpointsForSelection(_selection);
 
-    Rect editingRegion = Rect.fromPoints(
+    final editingRegion = Rect.fromPoints(
       renderObject!.localToGlobal(Offset.zero),
       renderObject!.localToGlobal(renderObject!.size.bottomRight(Offset.zero)),
     );
 
-    double baseLineHeight = renderObject!.preferredLineHeight(_selection.base);
-    double extentLineHeight =
+    final baseLineHeight = renderObject!.preferredLineHeight(_selection.base);
+    final extentLineHeight =
         renderObject!.preferredLineHeight(_selection.extent);
-    double smallestLineHeight = math.min(baseLineHeight, extentLineHeight);
-    bool isMultiline = endpoints.last.point.dy - endpoints.first.point.dy >
+    final smallestLineHeight = math.min(baseLineHeight, extentLineHeight);
+    final isMultiline = endpoints.last.point.dy - endpoints.first.point.dy >
         smallestLineHeight / 2;
 
-    double midX = isMultiline
+    final midX = isMultiline
         ? editingRegion.width / 2
         : (endpoints.first.point.dx + endpoints.last.point.dx) / 2;
 
-    Offset midpoint = Offset(
+    final midpoint = Offset(
       midX,
       endpoints[0].point.dy - baseLineHeight,
     );
@@ -326,14 +325,14 @@ class _TextSelectionHandleOverlayState
   void _handleDragStart(DragStartDetails details) {}
 
   void _handleDragUpdate(DragUpdateDetails details) {
-    TextPosition position =
+    final position =
         widget.renderObject!.getPositionForOffset(details.globalPosition);
     if (widget.selection.isCollapsed) {
       widget.onSelectionHandleChanged(TextSelection.fromPosition(position));
       return;
     }
 
-    bool isNormalized =
+    final isNormalized =
         widget.selection.extentOffset >= widget.selection.baseOffset;
     TextSelection? newSelection;
     switch (widget.position) {
@@ -389,27 +388,26 @@ class _TextSelectionHandleOverlayState
         break;
     }
 
-    TextPosition textPosition =
-        widget.position == _TextSelectionHandlePosition.START
-            ? widget.selection.base
-            : widget.selection.extent;
-    double lineHeight = widget.renderObject!.preferredLineHeight(textPosition);
-    Offset handleAnchor =
+    final textPosition = widget.position == _TextSelectionHandlePosition.START
+        ? widget.selection.base
+        : widget.selection.extent;
+    final lineHeight = widget.renderObject!.preferredLineHeight(textPosition);
+    final handleAnchor =
         widget.selectionControls.getHandleAnchor(type!, lineHeight);
-    Size handleSize = widget.selectionControls.getHandleSize(lineHeight);
+    final handleSize = widget.selectionControls.getHandleSize(lineHeight);
 
-    Rect handleRect = Rect.fromLTWH(
+    final handleRect = Rect.fromLTWH(
       -handleAnchor.dx,
       -handleAnchor.dy,
       handleSize.width,
       handleSize.height,
     );
 
-    Rect interactiveRect = handleRect.expandToInclude(
+    final interactiveRect = handleRect.expandToInclude(
       Rect.fromCircle(
           center: handleRect.center, radius: kMinInteractiveDimension / 2),
     );
-    RelativeRect padding = RelativeRect.fromLTRB(
+    final padding = RelativeRect.fromLTRB(
       math.max((interactiveRect.width - handleRect.width) / 2, 0),
       math.max((interactiveRect.height - handleRect.height) / 2, 0),
       math.max((interactiveRect.width - handleRect.width) / 2, 0),
@@ -656,8 +654,7 @@ class _EditorTextSelectionGestureDetectorState
 
   @override
   Widget build(BuildContext context) {
-    final Map<Type, GestureRecognizerFactory> gestures =
-        <Type, GestureRecognizerFactory>{};
+    final gestures = <Type, GestureRecognizerFactory>{};
 
     gestures[TapGestureRecognizer] =
         GestureRecognizerFactoryWithHandlers<TapGestureRecognizer>(

lib/widgets/toolbar.dart

@@ -215,7 +215,7 @@ class _ToggleStyleButtonState extends State<ToggleStyleButton> {
 
   bool _getIsToggled(Map<String, Attribute> attrs) {
     if (widget.attribute.key == Attribute.list.key) {
-      Attribute? attribute = attrs[widget.attribute.key];
+      final attribute = attrs[widget.attribute.key];
       if (attribute == null) {
         return false;
       }
@@ -299,7 +299,7 @@ class _ToggleCheckListButtonState extends State<ToggleCheckListButton> {
 
   bool _getIsToggled(Map<String, Attribute> attrs) {
     if (widget.attribute.key == Attribute.list.key) {
-      Attribute? attribute = attrs[widget.attribute.key];
+      final attribute = attrs[widget.attribute.key];
       if (attribute == null) {
         return false;
       }
@@ -430,20 +430,20 @@ class _SelectHeaderStyleButtonState extends State<SelectHeaderStyleButton> {
 
 Widget _selectHeadingStyleButtonBuilder(BuildContext context, Attribute? value,
     ValueChanged<Attribute?> onSelected) {
-  final Map<Attribute, String> _valueToText = {
+  final _valueToText = <Attribute, String>{
     Attribute.header: 'N',
     Attribute.h1: 'H1',
     Attribute.h2: 'H2',
     Attribute.h3: 'H3',
   };
 
-  List<Attribute> _valueAttribute = [
+  final _valueAttribute = <Attribute>[
     Attribute.header,
     Attribute.h1,
     Attribute.h2,
     Attribute.h3
   ];
-  List<String> _valueString = ['N', 'H1', 'H2', 'H3'];
+  final _valueString = <String>['N', 'H1', 'H2', 'H3'];
 
   final theme = Theme.of(context);
   final style = TextStyle(
@@ -520,10 +520,10 @@ class _ImageButtonState extends State<ImageButton> {
   final FileType _pickingType = FileType.any;
 
   Future<String?> _pickImage(ImageSource source) async {
-    final PickedFile? pickedFile = await _picker.getImage(source: source);
+    final pickedFile = await _picker.getImage(source: source);
     if (pickedFile == null) return null;
 
-    final File file = File(pickedFile.path);
+    final file = File(pickedFile.path);
 
     return widget.onImagePickCallback!(file);
   }
@@ -536,11 +536,11 @@ class _ImageButtonState extends State<ImageButton> {
           : null,
     ))
         ?.files;
-    var _fileName =
+    final _fileName =
         _paths != null ? _paths!.map((e) => e.name).toString() : '...';
 
     if (_paths != null) {
-      File file = File(_fileName);
+      final file = File(_fileName);
       // We simply return the absolute path to selected file.
       return widget.onImagePickCallback!(file);
     } else {
@@ -550,7 +550,7 @@ class _ImageButtonState extends State<ImageButton> {
   }
 
   Future<String> _pickImageDesktop() async {
-    var filePath = await FilesystemPicker.open(
+    final filePath = await FilesystemPicker.open(
       context: context,
       rootDirectory: await getApplicationDocumentsDirectory(),
       fsType: FilesystemType.file,
@@ -558,7 +558,7 @@ class _ImageButtonState extends State<ImageButton> {
     );
     if (filePath != null && filePath.isEmpty) return '';
 
-    final File file = File(filePath!);
+    final file = File(filePath!);
     return widget.onImagePickCallback!(file);
   }
 
@@ -683,19 +683,19 @@ class _ColorButtonState extends State<ColorButton> {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
-    Color? iconColor = _isToggledColor && !widget.background && !_isWhite
+    final iconColor = _isToggledColor && !widget.background && !_isWhite
         ? stringToColor(_selectionStyle.attributes['color']!.value)
         : theme.iconTheme.color;
 
-    var iconColorBackground =
+    final iconColorBackground =
         _isToggledBackground && widget.background && !_isWhitebackground
             ? stringToColor(_selectionStyle.attributes['background']!.value)
             : theme.iconTheme.color;
 
-    Color fillColor = _isToggledColor && !widget.background && _isWhite
+    final fillColor = _isToggledColor && !widget.background && _isWhite
         ? stringToColor('#ffffff')
         : theme.canvasColor;
-    Color fillColorBackground =
+    final fillColorBackground =
         _isToggledBackground && widget.background && _isWhitebackground
             ? stringToColor('#ffffff')
             : theme.canvasColor;
@@ -713,7 +713,7 @@ class _ColorButtonState extends State<ColorButton> {
   }
 
   void _changeColor(Color color) {
-    String hex = color.value.toRadixString(16);
+    var hex = color.value.toRadixString(16);
     if (hex.startsWith('ff')) {
       hex = hex.substring(2);
     }
@@ -894,7 +894,7 @@ class _ClearFormatButtonState extends State<ClearFormatButton> {
         icon: Icon(widget.icon, size: iconSize, color: iconColor),
         fillColor: fillColor,
         onPressed: () {
-          for (Attribute k
+          for (final k
               in widget.controller.getSelectionStyle().attributes.values) {
             widget.controller.formatSelection(Attribute.clone(k, null));
           }