draft-js
Version:
A React framework for building text editors.
231 lines (198 loc) • 8.28 kB
Flow
/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
* @flow strict-local
* @emails oncall+draft_js
*/
'use strict';
import type DraftEditor from "./DraftEditor.react";
const DOMObserver = require("./DOMObserver");
const DraftModifier = require("./DraftModifier");
const DraftOffsetKey = require("./DraftOffsetKey");
const EditorState = require("./EditorState");
const Keys = require("fbjs/lib/Keys");
const UserAgent = require("fbjs/lib/UserAgent");
const editOnSelect = require("./editOnSelect");
const getContentEditableContainer = require("./getContentEditableContainer");
const getDraftEditorSelection = require("./getDraftEditorSelection");
const getEntityKeyForSelection = require("./getEntityKeyForSelection");
const nullthrows = require("fbjs/lib/nullthrows");
const isIE = UserAgent.isBrowser('IE');
/**
* Millisecond delay to allow `compositionstart` to fire again upon
* `compositionend`.
*
* This is used for Korean input to ensure that typing can continue without
* the editor trying to render too quickly. More specifically, Safari 7.1+
* triggers `compositionstart` a little slower than Chrome/FF, which
* leads to composed characters being resolved and re-render occurring
* sooner than we want.
*/
const RESOLVE_DELAY = 20;
/**
* A handful of variables used to track the current composition and its
* resolution status. These exist at the module level because it is not
* possible to have compositions occurring in multiple editors simultaneously,
* and it simplifies state management with respect to the DraftEditor component.
*/
let resolved = false;
let stillComposing = false;
let domObserver = null;
function startDOMObserver(editor: DraftEditor) {
if (!domObserver) {
domObserver = new DOMObserver(getContentEditableContainer(editor));
domObserver.start();
}
}
const DraftEditorCompositionHandler = {
/**
* A `compositionstart` event has fired while we're still in composition
* mode. Continue the current composition session to prevent a re-render.
*/
onCompositionStart(editor: DraftEditor): void {
stillComposing = true;
startDOMObserver(editor);
},
/**
* Attempt to end the current composition session.
*
* Defer handling because browser will still insert the chars into active
* element after `compositionend`. If a `compositionstart` event fires
* before `resolveComposition` executes, our composition session will
* continue.
*
* The `resolved` flag is useful because certain IME interfaces fire the
* `compositionend` event multiple times, thus queueing up multiple attempts
* at handling the composition. Since handling the same composition event
* twice could break the DOM, we only use the first event. Example: Arabic
* Google Input Tools on Windows 8.1 fires `compositionend` three times.
*/
onCompositionEnd(editor: DraftEditor): void {
resolved = false;
stillComposing = false;
setTimeout(() => {
if (!resolved) {
DraftEditorCompositionHandler.resolveComposition(editor);
}
}, RESOLVE_DELAY);
},
onSelect: editOnSelect,
/**
* In Safari, keydown events may fire when committing compositions. If
* the arrow keys are used to commit, prevent default so that the cursor
* doesn't move, otherwise it will jump back noticeably on re-render.
*/
onKeyDown(editor: DraftEditor, e: SyntheticKeyboardEvent<>): void {
if (!stillComposing) {
// If a keydown event is received after compositionend but before the
// 20ms timer expires (ex: type option-E then backspace, or type A then
// backspace in 2-Set Korean), we should immediately resolve the
// composition and reinterpret the key press in edit mode.
DraftEditorCompositionHandler.resolveComposition(editor);
editor._onKeyDown(e);
return;
}
if (e.which === Keys.RIGHT || e.which === Keys.LEFT) {
e.preventDefault();
}
},
/**
* Keypress events may fire when committing compositions. In Firefox,
* pressing RETURN commits the composition and inserts extra newline
* characters that we do not want. `preventDefault` allows the composition
* to be committed while preventing the extra characters.
*/
onKeyPress(_editor: DraftEditor, e: SyntheticKeyboardEvent<>): void {
if (e.which === Keys.RETURN) {
e.preventDefault();
}
},
/**
* Attempt to insert composed characters into the document.
*
* If we are still in a composition session, do nothing. Otherwise, insert
* the characters into the document and terminate the composition session.
*
* If no characters were composed -- for instance, the user
* deleted all composed characters and committed nothing new --
* force a re-render. We also re-render when the composition occurs
* at the beginning of a leaf, to ensure that if the browser has
* created a new text node for the composition, we will discard it.
*
* Resetting innerHTML will move focus to the beginning of the editor,
* so we update to force it back to the correct place.
*/
resolveComposition(editor: DraftEditor): void {
if (stillComposing) {
return;
}
const mutations = nullthrows(domObserver).stopAndFlushMutations();
domObserver = null;
resolved = true;
let editorState = EditorState.set(editor._latestEditorState, {
inCompositionMode: false
});
editor.exitCurrentMode();
if (!mutations.size) {
editor.update(editorState);
return;
} // TODO, check if Facebook still needs this flag or if it could be removed.
// Since there can be multiple mutations providing a `composedChars` doesn't
// apply well on this new model.
// if (
// gkx('draft_handlebeforeinput_composed_text') &&
// editor.props.handleBeforeInput &&
// isEventHandled(
// editor.props.handleBeforeInput(
// composedChars,
// editorState,
// event.timeStamp,
// ),
// )
// ) {
// return;
// }
let contentState = editorState.getCurrentContent();
mutations.forEach((composedChars, offsetKey) => {
const {
blockKey,
decoratorKey,
leafKey
} = DraftOffsetKey.decode(offsetKey);
const {
start,
end
} = editorState.getBlockTree(blockKey).getIn([decoratorKey, 'leaves', leafKey]);
const replacementRange = editorState.getSelection().merge({
anchorKey: blockKey,
focusKey: blockKey,
anchorOffset: start,
focusOffset: end,
isBackward: false
});
const entityKey = getEntityKeyForSelection(contentState, replacementRange);
const currentStyle = contentState.getBlockForKey(blockKey).getInlineStyleAt(start);
contentState = DraftModifier.replaceText(contentState, replacementRange, composedChars, currentStyle, entityKey); // We need to update the editorState so the leaf node ranges are properly
// updated and multiple mutations are correctly applied.
editorState = EditorState.set(editorState, {
currentContent: contentState
});
}); // When we apply the text changes to the ContentState, the selection always
// goes to the end of the field, but it should just stay where it is
// after compositionEnd.
const documentSelection = getDraftEditorSelection(editorState, getContentEditableContainer(editor));
const compositionEndSelectionState = documentSelection.selectionState;
editor.restoreEditorDOM(); // See:
// - https://github.com/facebook/draft-js/issues/2093
// - https://github.com/facebook/draft-js/pull/2094
// Apply this fix only in IE for now. We can test it in
// other browsers in the future to ensure no regressions
const editorStateWithUpdatedSelection = isIE ? EditorState.forceSelection(editorState, compositionEndSelectionState) : EditorState.acceptSelection(editorState, compositionEndSelectionState);
editor.update(EditorState.push(editorStateWithUpdatedSelection, contentState, 'insert-characters'));
}
};
module.exports = DraftEditorCompositionHandler;