Create struct for history items

lib/flutter_quill.dart

@@ -9,6 +9,7 @@ export 'src/models/documents/nodes/line.dart';
 export 'src/models/documents/nodes/node.dart';
 export 'src/models/documents/style.dart';
 export 'src/models/quill_delta.dart';
+export 'src/models/structs/doc_change.dart';
 export 'src/models/structs/vertical_spacing.dart';
 export 'src/models/themes/quill_custom_button.dart';
 export 'src/models/themes/quill_dialog_theme.dart';

lib/src/models/documents/document.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 
 import '../quill_delta.dart';
 import '../rules/rule.dart';
+import '../structs/doc_change.dart';
 import 'attribute.dart';
 import 'history.dart';
 import 'nodes/block.dart';
@@ -48,13 +49,12 @@ class Document {
     _rules.setCustomRules(customRules);
   }
 
-  final StreamController<Tuple3<Delta, Delta, ChangeSource>> _observer =
+  final StreamController<DocChange> _observer = StreamController.broadcast();
-      StreamController.broadcast();
 
   final History _history = History();
 
-  /// Stream of [Change]s applied to this document.
+  /// Stream of [DocChange]s applied to this document.
-  Stream<Tuple3<Delta, Delta, ChangeSource>> get changes => _observer.stream;
+  Stream<DocChange> get changes => _observer.stream;
 
   /// Inserts [data] in this document at specified [index].
   ///
@@ -274,7 +274,7 @@ class Document {
     if (_delta != _root.toDelta()) {
       throw 'Compose failed';
     }
-    final change = Tuple3(originalDelta, delta, changeSource);
+    final change = DocChange(originalDelta, delta, changeSource);
     _observer.add(change);
     _history.handleDocChange(change);
   }

lib/src/models/documents/history.dart

@@ -1,5 +1,5 @@
-
 import '../quill_delta.dart';
+import '../structs/doc_change.dart';
 import 'document.dart';
 
 class History {
@@ -31,12 +31,12 @@ class History {
   ///record delay
   final int interval;
 
-  void handleDocChange(Tuple3<Delta, Delta, ChangeSource> change) {
+  void handleDocChange(DocChange docChange) {
     if (ignoreChange) return;
-    if (!userOnly || change.item3 == ChangeSource.LOCAL) {
+    if (!userOnly || docChange.source == ChangeSource.LOCAL) {
-      record(change.item2, change.item1);
+      record(docChange.change, docChange.before);
     } else {
-      transform(change.item2);
+      transform(docChange.change);
     }
   }
 

lib/src/models/structs/doc_change.dart

@@ -0,0 +1,18 @@
+import '../../../flutter_quill.dart';
+
+class DocChange {
+  DocChange(
+    this.before,
+    this.change,
+    this.source,
+  );
+
+  /// Document state before [change].
+  final Delta before;
+
+  /// Change delta applied to the document.
+  final Delta change;
+
+  /// The source of this change.
+  final ChangeSource source;
+}

lib/src/widgets/controller.dart

@@ -9,6 +9,7 @@ import '../models/documents/nodes/embeddable.dart';
 import '../models/documents/nodes/leaf.dart';
 import '../models/documents/style.dart';
 import '../models/quill_delta.dart';
+import '../models/structs/doc_change.dart';
 import '../utils/delta.dart';
 
 typedef ReplaceTextCallback = bool Function(int index, int len, Object? data);
@@ -81,12 +82,7 @@ class QuillController extends ChangeNotifier {
   /// removing or listeners to this instance.
   bool _isDisposed = false;
 
-  // item1: Document state before [change].
+  Stream<DocChange> get changes => document.changes;
-  //
-  // item2: Change delta applied to the document.
-  //
-  // item3: The source of this change.
-  Stream<Tuple3<Delta, Delta, ChangeSource>> get changes => document.changes;
 
   TextEditingValue get plainTextEditingValue => TextEditingValue(
         text: document.toPlainText(),