chore: refactor character replacement (#570)

lib/src/editor/editor_component/service/shortcuts/character/double/format_arrow_character.dart

@@ -1,4 +1,5 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:appflowy_editor/src/editor/editor_component/service/shortcuts/character_shortcut_events/format_double_characters/utils.dart';
 
 const _greater = '>';
 const _equals = '=';
@@ -14,62 +15,10 @@ const _arrow = '⇒';
 final CharacterShortcutEvent formatGreaterEqual = CharacterShortcutEvent(
   key: 'format = + > into ⇒',
   character: _greater,
-  handler: (editorState) async => handleEqualGreaterReplacement(
+  handler: (editorState) async => handleDoubleCharacterReplacement(
     editorState: editorState,
     character: _greater,
     replacement: _arrow,
+    prefixCharacter: _equals,
   ),
 );
-
-// TODO(Xazin): Combine two character replacement methods into
-//  a helper function
-Future<bool> handleEqualGreaterReplacement({
-  required EditorState editorState,
-  required String character,
-  required String replacement,
-}) async {
-  assert(character.length == 1);
-
-  Selection? selection = editorState.selection;
-  if (selection == null) {
-    return false;
-  }
-
-  if (!selection.isCollapsed) {
-    await editorState.deleteSelection(selection);
-  }
-
-  selection = editorState.selection;
-  if (selection == null) {
-    return false;
-  }
-
-  final node = editorState.getNodeAtPath(selection.end.path);
-  final delta = node?.delta;
-  if (node == null || delta == null || delta.isEmpty) {
-    return false;
-  }
-
-  if (selection.end.offset > 0) {
-    final plain = delta.toPlainText();
-
-    final previousCharacter = plain[selection.end.offset - 1];
-    if (previousCharacter != _equals) {
-      return false;
-    }
-
-    final replace = editorState.transaction
-      ..replaceText(
-        node,
-        selection.end.offset - 1,
-        1,
-        _arrow,
-      );
-
-    await editorState.apply(replace);
-
-    return true;
-  }
-
-  return false;
-}

lib/src/editor/editor_component/service/shortcuts/character/double/format_double_hyphen.dart

@@ -1,4 +1,5 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:appflowy_editor/src/editor/editor_component/service/shortcuts/character_shortcut_events/format_double_characters/utils.dart';
 
 const _hyphen = '-';
 const _emDash = '—'; // This is an em dash — not a single dash - !!
@@ -19,54 +20,3 @@ final CharacterShortcutEvent formatDoubleHyphenEmDash = CharacterShortcutEvent(
     replacement: _emDash,
   ),
 );
-
-Future<bool> handleDoubleCharacterReplacement({
-  required EditorState editorState,
-  required String character,
-  required String replacement,
-}) async {
-  assert(character.length == 1);
-
-  Selection? selection = editorState.selection;
-  if (selection == null) {
-    return false;
-  }
-
-  if (!selection.isCollapsed) {
-    await editorState.deleteSelection(selection);
-  }
-
-  selection = editorState.selection;
-  if (selection == null) {
-    return false;
-  }
-
-  final node = editorState.getNodeAtPath(selection.end.path);
-  final delta = node?.delta;
-  if (node == null || delta == null || delta.isEmpty) {
-    return false;
-  }
-
-  if (selection.end.offset > 0) {
-    final plain = delta.toPlainText();
-
-    final previousCharacter = plain[selection.end.offset - 1];
-    if (previousCharacter != _hyphen) {
-      return false;
-    }
-
-    final replace = editorState.transaction
-      ..replaceText(
-        node,
-        selection.end.offset - 1,
-        1,
-        _emDash,
-      );
-
-    await editorState.apply(replace);
-
-    return true;
-  }
-
-  return false;
-}

lib/src/editor/editor_component/service/shortcuts/character_shortcut_events/format_double_characters/utils.dart

@@ -0,0 +1,57 @@
+import 'package:appflowy_editor/appflowy_editor.dart';
+
+/// If [prefixCharacter] is null or empty, [character] is used
+Future<bool> handleDoubleCharacterReplacement({
+  required EditorState editorState,
+  required String character,
+  required String replacement,
+  String? prefixCharacter,
+}) async {
+  assert(character.length == 1);
+
+  Selection? selection = editorState.selection;
+  if (selection == null) {
+    return false;
+  }
+
+  if (!selection.isCollapsed) {
+    await editorState.deleteSelection(selection);
+  }
+
+  selection = editorState.selection;
+  if (selection == null) {
+    return false;
+  }
+
+  final node = editorState.getNodeAtPath(selection.end.path);
+  final delta = node?.delta;
+  if (node == null || delta == null || delta.isEmpty) {
+    return false;
+  }
+
+  if (selection.end.offset > 0) {
+    final plain = delta.toPlainText();
+
+    final expectedPrevious =
+        prefixCharacter?.isEmpty ?? true ? character : prefixCharacter;
+
+    final previousCharacter = plain[selection.end.offset - 1];
+    if (previousCharacter != expectedPrevious) {
+      return false;
+    }
+
+    final replace = editorState.transaction
+      ..replaceText(
+        node,
+        selection.end.offset - 1,
+        1,
+        replacement,
+      );
+
+    await editorState.apply(replace);
+
+    return true;
+  }
+
+  return false;
+}