draft-js/lib/DraftEntitySegments.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 { DraftRange } from "./DraftRange";
import type { DraftRemovalDirection } from "./DraftRemovalDirection";
/**
 * Identify the range to delete from a segmented entity.
 *
 * Rules:
 *
 *  Example: 'John F. Kennedy'
 *
 *   - Deletion from within any non-whitespace (i.e. ['John', 'F.', 'Kennedy'])
 *     will return the range of that text.
 *
 *       'John F. Kennedy' -> 'John F.'
 *                  ^
 *
 *   - Forward deletion of whitespace will remove the following section:
 *
 *       'John F. Kennedy' -> 'John Kennedy'
 *            ^
 *
 *   - Backward deletion of whitespace will remove the previous section:
 *
 *       'John F. Kennedy' -> 'F. Kennedy'
 *            ^
 */

const DraftEntitySegments = {
  getRemovalRange: function (selectionStart: number, selectionEnd: number, text: string, entityStart: number, direction: DraftRemovalDirection): DraftRange {
    let segments = text.split(' ');
    segments = segments.map((
    /*string*/
    segment,
    /*number*/
    ii) => {
      if (direction === 'forward') {
        if (ii > 0) {
          return ' ' + segment;
        }
      } else if (ii < segments.length - 1) {
        return segment + ' ';
      }

      return segment;
    });
    let segmentStart = entityStart;
    let segmentEnd;
    let segment;
    let removalStart: any = null;
    let removalEnd: any = null;

    for (let jj = 0; jj < segments.length; jj++) {
      segment = segments[jj];
      segmentEnd = segmentStart + segment.length; // Our selection overlaps this segment.

      if (selectionStart < segmentEnd && segmentStart < selectionEnd) {
        if (removalStart !== null) {
          removalEnd = segmentEnd;
        } else {
          removalStart = segmentStart;
          removalEnd = segmentEnd;
        }
      } else if (removalStart !== null) {
        break;
      }

      segmentStart = segmentEnd;
    }

    const entityEnd = entityStart + text.length;
    const atStart = removalStart === entityStart;
    const atEnd = removalEnd === entityEnd;

    if (!atStart && atEnd || atStart && !atEnd) {
      if (direction === 'forward') {
        if (removalEnd !== entityEnd) {
          removalEnd++;
        }
      } else if (removalStart !== entityStart) {
        removalStart--;
      }
    }

    return {
      start: removalStart,
      end: removalEnd
    };
  }
};
module.exports = DraftEntitySegments;