feat: delete sentence shortcut

Closes: #4

lib/src/service/internal_key_event_handlers/arrow_keys_handler.dart

@@ -191,6 +191,7 @@ ShortcutEventHandler cursorBeginSelect = (editorState, event) {
   if (position != null) {
     end = position;
   }
+
   editorState.service.selectionService.updateSelection(
     selection.copyWith(start: start, end: end),
   );
@@ -349,6 +350,45 @@ ShortcutEventHandler cursorLeftWordDelete = (editorState, event) {
   return KeyEventResult.handled;
 };
 
+ShortcutEventHandler cursorLeftSentenceDelete = (editorState, event) {
+  final nodes = editorState.service.selectionService.currentSelectedNodes;
+  final selection = editorState.service.selectionService.currentSelection.value;
+  if (nodes.isEmpty || selection == null) {
+    return KeyEventResult.ignored;
+  }
+
+  if (nodes.length == 1 && nodes.first is TextNode) {
+    final textNode = nodes.first as TextNode;
+    if (textNode.toPlainText().isEmpty) {
+      return KeyEventResult.ignored;
+    }
+  }
+
+  final deleteTransaction = editorState.transaction;
+  deleteTransaction.deleteNodes(
+    editorState.service.selectionService.getNodesInSelection(selection),
+  );
+  editorState.apply(deleteTransaction, withUpdateCursor: false);
+
+  final cursorPosition =
+      selection.start.copyWith(offset: 0).goLeft(editorState);
+  if (cursorPosition != null) {
+    final next = cursorPosition.path.next;
+    final transaction = editorState.transaction
+      ..insertNode(
+        next,
+        TextNode.empty(),
+      )
+      ..afterSelection = Selection.collapsed(
+        Position(path: next, offset: 0),
+      );
+
+    editorState.apply(transaction);
+  }
+
+  return KeyEventResult.handled;
+};
+
 enum _SelectionRange {
   character,
   word,

lib/src/service/shortcut_event/built_in_shortcut_events.dart

@@ -63,11 +63,18 @@ List<ShortcutEvent> builtInShortcutEvents = [
   ),
   ShortcutEvent(
     key: 'Cursor word delete',
-    command: 'meta+backspace',
+    command: 'alt+backspace',
     windowsCommand: 'ctrl+backspace',
     linuxCommand: 'ctrl+backspace',
     handler: cursorLeftWordDelete,
   ),
+  ShortcutEvent(
+    key: 'Cursor sentence delete',
+    command: 'meta+backspace',
+    windowsCommand: 'alt+backspace',
+    linuxCommand: 'alt+backspace',
+    handler: cursorLeftSentenceDelete,
+  ),
   ShortcutEvent(
     key: 'Cursor left select',
     command: 'shift+arrow left',

test/service/internal_key_event_handlers/backspace_handler_test.dart

@@ -59,6 +59,7 @@ void main() async {
       (tester) async {
     await _deleteTextByBackspace(tester, true);
   });
+
   testWidgets(
       'Presses backspace key in non-empty document and selection is forward',
       (tester) async {
@@ -85,6 +86,7 @@ void main() async {
       (tester) async {
     await _deleteTextByDelete(tester, true);
   });
+
   testWidgets(
       'Presses delete key in non-empty document and selection is forward',
       (tester) async {
@@ -135,14 +137,17 @@ void main() async {
       (tester) async {
     await _deleteStyledTextByBackspace(tester, BuiltInAttributeKey.checkbox);
   });
+
   testWidgets('Presses backspace key in styled text (bulletedList)',
       (tester) async {
     await _deleteStyledTextByBackspace(
         tester, BuiltInAttributeKey.bulletedList);
   });
+
   testWidgets('Presses backspace key in styled text (heading)', (tester) async {
     await _deleteStyledTextByBackspace(tester, BuiltInAttributeKey.heading);
   });
+
   testWidgets('Presses backspace key in styled text (quote)', (tester) async {
     await _deleteStyledTextByBackspace(tester, BuiltInAttributeKey.quote);
   });
@@ -161,13 +166,16 @@ void main() async {
   testWidgets('Presses delete key in styled text (checkbox)', (tester) async {
     await _deleteStyledTextByDelete(tester, BuiltInAttributeKey.checkbox);
   });
+
   testWidgets('Presses delete key in styled text (bulletedList)',
       (tester) async {
     await _deleteStyledTextByDelete(tester, BuiltInAttributeKey.bulletedList);
   });
+
   testWidgets('Presses delete key in styled text (heading)', (tester) async {
     await _deleteStyledTextByDelete(tester, BuiltInAttributeKey.heading);
   });
+
   testWidgets('Presses delete key in styled text (quote)', (tester) async {
     await _deleteStyledTextByDelete(tester, BuiltInAttributeKey.quote);
   });
@@ -251,7 +259,7 @@ void main() async {
     await editor.insertText(textNode, '#', 0);
     await editor.pressLogicKey(LogicalKeyboardKey.space);
     expect(
-      (editor.nodeAtPath([0]) as TextNode).attributes.heading,
+      textNode.attributes.heading,
       BuiltInAttributeKey.h1,
     );
 
@@ -264,7 +272,7 @@ void main() async {
     await editor.insertText(textNode, '#', 0);
     await editor.pressLogicKey(LogicalKeyboardKey.space);
     expect(
-      (editor.nodeAtPath([0]) as TextNode).attributes.heading,
+      textNode.attributes.heading,
       BuiltInAttributeKey.h1,
     );
   });
@@ -297,24 +305,31 @@ void main() async {
       Selection.single(path: [0, 0, 0], startOffset: 0),
     );
     await editor.pressLogicKey(LogicalKeyboardKey.backspace);
+
     expect(editor.nodeAtPath([0, 0, 0])?.subtype, null);
+
     await editor.updateSelection(
       Selection.single(path: [0, 0, 0], startOffset: 0),
     );
     await editor.pressLogicKey(LogicalKeyboardKey.backspace);
+
     expect(editor.nodeAtPath([0, 1]) != null, true);
+
     await editor.updateSelection(
       Selection.single(path: [0, 1], startOffset: 0),
     );
     await editor.pressLogicKey(LogicalKeyboardKey.backspace);
+
     expect(editor.nodeAtPath([1]) != null, true);
+
     await editor.updateSelection(
       Selection.single(path: [1], startOffset: 0),
     );
 
     // * Welcome to Appflowy 😁
     //  * Welcome to Appflowy 😁Welcome to Appflowy 😁
     await editor.pressLogicKey(LogicalKeyboardKey.backspace);
+
     expect(
       editor.documentSelection,
       Selection.single(path: [0, 0], startOffset: text.length),
@@ -357,18 +372,22 @@ void main() async {
       Selection.single(path: [0, 1], startOffset: 0),
     );
     await editor.pressLogicKey(LogicalKeyboardKey.backspace);
+
     expect(
       editor.nodeAtPath([0, 1])!.subtype != BuiltInAttributeKey.bulletedList,
       true,
     );
+
     expect(
       editor.nodeAtPath([0, 1, 0])!.subtype,
       BuiltInAttributeKey.bulletedList,
     );
+
     expect(
       editor.nodeAtPath([0, 1, 1])!.subtype,
       BuiltInAttributeKey.bulletedList,
     );
+
     expect(find.byType(FlowyRichText), findsNWidgets(5));
 
     // Before
@@ -383,18 +402,22 @@ void main() async {
     //  * Welcome to Appflowy 😁
     //  * Welcome to Appflowy 😁
     await editor.pressLogicKey(LogicalKeyboardKey.backspace);
+
     expect(
       editor.nodeAtPath([0, 0])!.subtype == BuiltInAttributeKey.bulletedList,
       true,
     );
+
     expect(
       (editor.nodeAtPath([0, 0]) as TextNode).toPlainText() == text * 2,
       true,
     );
+
     expect(
       editor.nodeAtPath([0, 1])!.subtype == BuiltInAttributeKey.bulletedList,
       true,
     );
+
     expect(
       editor.nodeAtPath([0, 2])!.subtype == BuiltInAttributeKey.bulletedList,
       true,