draft-js/lib/BlockTree.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 { BlockNodeRecord } from "./BlockNodeRecord";
import type CharacterMetadata from "./CharacterMetadata";
import type ContentState from "./ContentState";
import type { DraftDecoratorType } from "./DraftDecoratorType";

const findRangesImmutable = require("./findRangesImmutable");

const getOwnObjectValues = require("./getOwnObjectValues");

const Immutable = require("immutable");

const {
  List,
  Repeat,
  Record
} = Immutable;

const returnTrue = function () {
  return true;
};

const defaultLeafRange: {
  start: ?number,
  end: ?number,
  ...
} = {
  start: null,
  end: null
};
const LeafRange = (Record(defaultLeafRange): any);
export type DecoratorRangeRawType = {
  start: ?number,
  end: ?number,
  decoratorKey: ?string,
  leaves: ?Array<LeafRange>,
  ...
};
type DecoratorRangeType = {
  start: ?number,
  end: ?number,
  decoratorKey: ?string,
  leaves: ?List<LeafRange>,
  ...
};
const defaultDecoratorRange: DecoratorRangeType = {
  start: null,
  end: null,
  decoratorKey: null,
  leaves: null
};
const DecoratorRange = (Record(defaultDecoratorRange): any);
const BlockTree = {
  /**
   * Generate a block tree for a given ContentBlock/decorator pair.
   */
  generate(contentState: ContentState, block: BlockNodeRecord, decorator: ?DraftDecoratorType): List<DecoratorRange> {
    const textLength = block.getLength();

    if (!textLength) {
      return List.of(new DecoratorRange({
        start: 0,
        end: 0,
        decoratorKey: null,
        leaves: List.of(new LeafRange({
          start: 0,
          end: 0
        }))
      }));
    }

    const leafSets = [];
    const decorations = decorator ? decorator.getDecorations(block, contentState) : List(Repeat(null, textLength));
    const chars = block.getCharacterList();
    findRangesImmutable(decorations, areEqual, returnTrue, (start, end) => {
      leafSets.push(new DecoratorRange({
        start,
        end,
        decoratorKey: decorations.get(start),
        leaves: generateLeaves(chars.slice(start, end).toList(), start)
      }));
    });
    return List(leafSets);
  },

  fromJS({
    leaves,
    ...other
  }: DecoratorRangeRawType): DecoratorRange {
    return new DecoratorRange({ ...other,
      leaves: leaves != null ? List(Array.isArray(leaves) ? leaves : getOwnObjectValues(leaves)).map(leaf => LeafRange(leaf)) : null
    });
  }

};
/**
 * Generate LeafRange records for a given character list.
 */

function generateLeaves(characters: List<CharacterMetadata>, offset: number): List<LeafRange> {
  const leaves = [];
  const inlineStyles = characters.map(c => c.getStyle()).toList();
  findRangesImmutable(inlineStyles, areEqual, returnTrue, (start, end) => {
    leaves.push(new LeafRange({
      start: start + offset,
      end: end + offset
    }));
  });
  return List(leaves);
}

function areEqual(a: any, b: any): boolean {
  return a === b;
}

module.exports = BlockTree;