Fix IME bugs

* Suppress mutations when using an IME on a blank line
* Ignore control keydowns when IME is active
* Handle carriage return keypresses

src/js/editor/editor.js

@@ -150,6 +150,8 @@ class Editor {
     this._callbacks = new LifecycleCallbacks(values(CALLBACK_QUEUES))
     this._beforeHooks = { toggleMarkup: [] }
 
+    this._isComposingOnBlankLine = false
+
     DEFAULT_TEXT_INPUT_HANDLERS.forEach(handler => this.onTextInput(handler))
 
     this.hasRendered = false

src/js/editor/event-manager.js

@@ -6,7 +6,17 @@ import TextInputHandler from 'mobiledoc-kit/editor/text-input-handler'
 import SelectionManager from 'mobiledoc-kit/editor/selection-manager'
 import Browser from 'mobiledoc-kit/utils/browser'
 
-const ELEMENT_EVENT_TYPES = ['keydown', 'keyup', 'cut', 'copy', 'paste', 'keypress', 'drop']
+const ELEMENT_EVENT_TYPES = [
+  'keydown',
+  'keyup',
+  'cut',
+  'copy',
+  'paste',
+  'keypress',
+  'drop',
+  'compositionstart',
+  'compositionend',
+]
 
 export default class EventManager {
   constructor(editor) {
@@ -143,6 +153,13 @@ export default class EventManager {
       event.preventDefault()
     }
 
+    // Handle carriage returns
+    if (!key.isEnter() && key.keyCode === 13) {
+      _textInputHandler.handleNewLine()
+      editor.handleNewline(event)
+      return
+    }
+
     _textInputHandler.handle(key.toString())
   }
 
@@ -169,6 +186,10 @@ export default class EventManager {
     let range = editor.range
 
     switch (true) {
+      // Ignore keydown events when using an IME
+      case key.isIME(): {
+        break
+      }
       // FIXME This should be restricted to only card/atom boundaries
       case key.isHorizontalArrowWithoutModifiersOtherThanShift(): {
         let newRange
@@ -215,6 +236,59 @@ export default class EventManager {
     this._updateModifiersFromKey(key, { isDown: false })
   }
 
+  // The mutation handler interferes with IMEs when composing
+  // on a blank line. These two event handlers are for suppressing
+  // mutation handling in this scenario.
+  compositionstart(event) {
+    let { editor } = this
+    // Ignore compositionstart if not on a blank line
+    if (editor.range.headMarker) {
+      return
+    }
+    this._isComposingOnBlankLine = true
+
+    if (editor.post.isBlank) {
+      editor._insertEmptyMarkupSectionAtCursor()
+    }
+
+    // Stop listening for mutations on Chrome browsers and suppress
+    // mutations by prepending a character for other browsers.
+    // The reason why we treat these separately is because
+    // of the way each browser processes IME inputs.
+    if (Browser.isChrome()) {
+      editor.setPlaceholder('')
+      editor._mutationHandler.stopObserving()
+    } else {
+      this._textInputHandler.handle(' ')
+    }
+  }
+
+  compositionend(event) {
+    let { editor } = this
+
+    // Ignore compositionend if not composing on blank line
+    if (!this._isComposingOnBlankLine) {
+      return
+    }
+    this._isComposingOnBlankLine = false
+
+    // Start listening for mutations on Chrome browsers and
+    // delete the prepended character introduced by compositionstart
+    // for other browsers.
+    if (Browser.isChrome()) {
+      editor.insertText(event.data)
+      editor.setPlaceholder(editor.placeholder)
+      editor._mutationHandler.startObserving()
+    } else {
+      let startOfCompositionLine = editor.range.headSection.toPosition(0)
+      let endOfCompositionLine = editor.range.headSection.toPosition(event.data.length)
+      editor.run(postEditor => {
+        postEditor.deleteAtPosition(startOfCompositionLine, 1, { unit: 'char' })
+        postEditor.setRange(endOfCompositionLine)
+      })
+    }
+  }
+
   cut(event) {
     event.preventDefault()
 

src/js/utils/browser.ts

@@ -5,4 +5,7 @@ export default {
   isWin() {
     return typeof window !== 'undefined' && window.navigator && /Win/.test(window.navigator.platform)
   },
+  isChrome() {
+    return typeof window !== 'undefined' && 'chrome' in window
+  },
 }

tests/acceptance/editor-ime-handler-test.js

@@ -0,0 +1,93 @@
+import Keycodes from 'mobiledoc-kit/utils/keycodes';
+import Browser from 'mobiledoc-kit/utils/browser';
+import Helpers from '../test-helpers';
+
+let editor, editorElement;
+
+const { test, module } = Helpers;
+
+module('Acceptance: editor: IME Composition Event Handler', {
+  beforeEach() {
+    editorElement = $('#editor')[0];
+  },
+  afterEach() {
+    if (editor) { editor.destroy(); }
+  }
+});
+
+['Enter', 'Tab', 'Backspace'].forEach((key) => {
+  test(`ignore ${key} keydowns when using an IME`, (assert) => {
+    let { post: expected } = Helpers.postAbstract.buildFromText('你好');
+    editor = Helpers.editor.buildFromText('你好', { element: editorElement });
+
+    Helpers.dom.moveCursorTo(editor, editorElement.firstChild, 1);
+
+    Helpers.dom.triggerKeyEvent(editor, 'keydown', {
+      key,
+      keyCode: Keycodes.IME,
+      charCode: Keycodes[key.toUpperCase()]
+    });
+
+    assert.postIsSimilar(editor.post, expected);
+  });
+});
+
+test('ignore horizontal arrow keydowns when using IME', (assert) => {
+  editor = Helpers.editor.buildFromText("안녕하세요", { element: editorElement });
+
+  Helpers.dom.moveCursorTo(editor, editorElement.firstChild);
+
+  Helpers.dom.triggerKeyEvent(editor, 'keydown', {
+    key: 'ArrowRight',
+    keyCode: Keycodes.IME,
+    charCode: Keycodes.RIGHT
+  });
+
+  assert.positionIsEqual(editor.range.head, editor.post.headPosition());
+
+  Helpers.dom.moveCursorTo(editor, editorElement.firstChild, 1);
+
+  Helpers.dom.triggerKeyEvent(editor, 'keydown', {
+    key: 'ArrowLeft',
+    keyCode: Keycodes.IME,
+    charCode: Keycodes.LEFT
+  });
+
+  assert.positionIsEqual(editor.range.head, editor.post.tailPosition());
+});
+
+// There doesn't seem to be a way to directly test the usage
+// of an OS-level IME, however this test roughly simulates
+// how the IME inputs text into the DOM.
+test('test handling of IME composition events', (assert) => {
+  let done = assert.async();
+
+  editor = Helpers.editor.buildFromText("", { element: editorElement });
+
+  Helpers.dom.moveCursorTo(editor, editorElement);
+
+  editor.element.dispatchEvent(
+    new CompositionEvent('compositionstart', { 'data': 'n' })
+  );
+
+  Helpers.wait(() => {
+    if(Browser.isChrome()) {
+      editorElement.firstChild.innerHTML = "こんにちは"
+    } else {
+      editorElement.firstChild.innerHTML += "こんにちは"
+    }
+
+    Helpers.wait(() => {
+      editor.element.dispatchEvent(
+        new CompositionEvent('compositionend', { 'data': 'こんにちは' })
+      );
+
+      Helpers.wait(() => {
+        assert.positionIsEqual(editor.range.head, editor.post.tailPosition());
+        assert.hasElement('#editor p:contains(こんにちは)');
+
+        done();
+      });
+    });
+  });
+});