Add attribute class

lib/models/documents/attribute.dart

@@ -0,0 +1,28 @@
+enum AttributeScope {
+  INLINE, // refer to https://quilljs.com/docs/formats/#inline
+  BLOCK, // refer to https://quilljs.com/docs/formats/#block
+  EMBEDS, // refer to https://quilljs.com/docs/formats/#embeds
+}
+
+class Attribute<T> {
+  final String key;
+  final AttributeScope scope;
+
+  Attribute(this.key, this.scope);
+}
+
+class BoldAttribute extends Attribute<bool> {
+  BoldAttribute() : super('bold', AttributeScope.INLINE);
+}
+
+class ItalicAttribute extends Attribute<bool> {
+  ItalicAttribute() : super('italic', AttributeScope.INLINE);
+}
+
+class UnderlineAttribute extends Attribute<bool> {
+  UnderlineAttribute() : super('underline', AttributeScope.INLINE);
+}
+
+class StrikeThroughAttribute extends Attribute<bool> {
+  StrikeThroughAttribute() : super('strike', AttributeScope.INLINE);
+}

pubspec.lock

@@ -37,7 +37,7 @@ packages:
     source: hosted
     version: "1.1.0-nullsafety.1"
   collection:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: collection
       url: "https://pub.dartlang.org"
@@ -89,7 +89,7 @@ packages:
     source: hosted
     version: "2.0.0"
   quiver_hashcode:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: quiver_hashcode
       url: "https://pub.dartlang.org"

pubspec.yaml

@@ -13,6 +13,8 @@ dependencies:
   flutter:
     sdk: flutter
   quill_delta: ^2.0.0
+  quiver_hashcode: ^2.0.0
+  collection: ^1.14.13
 
 dev_dependencies:
   flutter_test: