draft-js/lib/EditorBidiService.js.flow

A React framework for building text editors.

/**
 * 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
 * @emails oncall+draft_js
 */
'use strict';

import type ContentState from "./ContentState";

const UnicodeBidiService = require("fbjs/lib/UnicodeBidiService");

const Immutable = require("immutable");

const nullthrows = require("fbjs/lib/nullthrows");

const {
  OrderedMap
} = Immutable;
let bidiService;
const EditorBidiService = {
  getDirectionMap: function (content: ContentState, prevBidiMap: ?OrderedMap<any, any>): OrderedMap<any, any> {
    if (!bidiService) {
      bidiService = new UnicodeBidiService();
    } else {
      bidiService.reset();
    }

    const blockMap = content.getBlockMap();
    const nextBidi = blockMap.valueSeq().map(block => nullthrows(bidiService).getDirection(block.getText()));
    const bidiMap = OrderedMap(blockMap.keySeq().zip(nextBidi));

    if (prevBidiMap != null && Immutable.is(prevBidiMap, bidiMap)) {
      return prevBidiMap;
    }

    return bidiMap;
  }
};
module.exports = EditorBidiService;