draft-js/lib/moveBlockInContentState.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 { BlockMap } from "./BlockMap";
import type { BlockNodeRecord } from "./BlockNodeRecord";
import type ContentState from "./ContentState";
import type { DraftInsertionType } from "./DraftInsertionType";

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

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

const Immutable = require("immutable");

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

const {
  OrderedMap,
  List
} = Immutable;

const transformBlock = (key: ?string, blockMap: BlockMap, func: ((block: ContentBlockNode) => ContentBlockNode)): void => {
  if (!key) {
    return;
  }

  const block = blockMap.get(key);

  if (!block) {
    return;
  }

  blockMap.set(key, func(block));
};

const updateBlockMapLinks = (blockMap: BlockMap, originalBlockToBeMoved: BlockNodeRecord, originalTargetBlock: BlockNodeRecord, insertionMode: DraftInsertionType, isExperimentalTreeBlock: boolean): BlockMap => {
  if (!isExperimentalTreeBlock) {
    return blockMap;
  } // possible values of 'insertionMode' are: 'after', 'before'


  const isInsertedAfterTarget = insertionMode === 'after';
  const originalBlockKey = originalBlockToBeMoved.getKey();
  const originalTargetKey = originalTargetBlock.getKey();
  const originalParentKey = originalBlockToBeMoved.getParentKey();
  const originalNextSiblingKey = originalBlockToBeMoved.getNextSiblingKey();
  const originalPrevSiblingKey = originalBlockToBeMoved.getPrevSiblingKey();
  const newParentKey = originalTargetBlock.getParentKey();
  const newNextSiblingKey = isInsertedAfterTarget ? originalTargetBlock.getNextSiblingKey() : originalTargetKey;
  const newPrevSiblingKey = isInsertedAfterTarget ? originalTargetKey : originalTargetBlock.getPrevSiblingKey();
  return blockMap.withMutations(blocks => {
    // update old parent
    transformBlock(originalParentKey, blocks, block => {
      const parentChildrenList = block.getChildKeys();
      return block.merge({
        children: parentChildrenList.delete(parentChildrenList.indexOf(originalBlockKey))
      });
    }); // update old prev

    transformBlock(originalPrevSiblingKey, blocks, block => block.merge({
      nextSibling: originalNextSiblingKey
    })); // update old next

    transformBlock(originalNextSiblingKey, blocks, block => block.merge({
      prevSibling: originalPrevSiblingKey
    })); // update new next

    transformBlock(newNextSiblingKey, blocks, block => block.merge({
      prevSibling: originalBlockKey
    })); // update new prev

    transformBlock(newPrevSiblingKey, blocks, block => block.merge({
      nextSibling: originalBlockKey
    })); // update new parent

    transformBlock(newParentKey, blocks, block => {
      const newParentChildrenList = block.getChildKeys();
      const targetBlockIndex = newParentChildrenList.indexOf(originalTargetKey);
      const insertionIndex = isInsertedAfterTarget ? targetBlockIndex + 1 : targetBlockIndex !== 0 ? targetBlockIndex - 1 : 0;
      const newChildrenArray = newParentChildrenList.toArray();
      newChildrenArray.splice(insertionIndex, 0, originalBlockKey);
      return block.merge({
        children: List(newChildrenArray)
      });
    }); // update block

    transformBlock(originalBlockKey, blocks, block => block.merge({
      nextSibling: newNextSiblingKey,
      prevSibling: newPrevSiblingKey,
      parent: newParentKey
    }));
  });
};

const moveBlockInContentState = (contentState: ContentState, blockToBeMoved: BlockNodeRecord, targetBlock: BlockNodeRecord, insertionMode: DraftInsertionType): ContentState => {
  invariant(insertionMode !== 'replace', 'Replacing blocks is not supported.');
  const targetKey = targetBlock.getKey();
  const blockKey = blockToBeMoved.getKey();
  invariant(blockKey !== targetKey, 'Block cannot be moved next to itself.');
  const blockMap = contentState.getBlockMap();
  const isExperimentalTreeBlock = blockToBeMoved instanceof ContentBlockNode;
  let blocksToBeMoved = [blockToBeMoved];
  let blockMapWithoutBlocksToBeMoved = blockMap.delete(blockKey);

  if (isExperimentalTreeBlock) {
    blocksToBeMoved = [];
    blockMapWithoutBlocksToBeMoved = blockMap.withMutations(blocks => {
      const nextSiblingKey = blockToBeMoved.getNextSiblingKey();
      const nextDelimiterBlockKey = getNextDelimiterBlockKey(blockToBeMoved, blocks);
      blocks.toSeq().skipUntil(block => block.getKey() === blockKey).takeWhile(block => {
        const key = block.getKey();
        const isBlockToBeMoved = key === blockKey;
        const hasNextSiblingAndIsNotNextSibling = nextSiblingKey && key !== nextSiblingKey;
        const doesNotHaveNextSiblingAndIsNotDelimiter = !nextSiblingKey && block.getParentKey() && (!nextDelimiterBlockKey || key !== nextDelimiterBlockKey);
        return !!(isBlockToBeMoved || hasNextSiblingAndIsNotNextSibling || doesNotHaveNextSiblingAndIsNotDelimiter);
      }).forEach(block => {
        blocksToBeMoved.push(block);
        blocks.delete(block.getKey());
      });
    });
  }

  const blocksBefore = blockMapWithoutBlocksToBeMoved.toSeq().takeUntil(v => v === targetBlock);
  const blocksAfter = blockMapWithoutBlocksToBeMoved.toSeq().skipUntil(v => v === targetBlock).skip(1);
  const slicedBlocks = blocksToBeMoved.map(block => [block.getKey(), block]);
  let newBlocks = OrderedMap();

  if (insertionMode === 'before') {
    const blockBefore = contentState.getBlockBefore(targetKey);
    invariant(!blockBefore || blockBefore.getKey() !== blockToBeMoved.getKey(), 'Block cannot be moved next to itself.');
    newBlocks = blocksBefore.concat([...slicedBlocks, [targetKey, targetBlock]], blocksAfter).toOrderedMap();
  } else if (insertionMode === 'after') {
    const blockAfter = contentState.getBlockAfter(targetKey);
    invariant(!blockAfter || blockAfter.getKey() !== blockKey, 'Block cannot be moved next to itself.');
    newBlocks = blocksBefore.concat([[targetKey, targetBlock], ...slicedBlocks], blocksAfter).toOrderedMap();
  }

  return contentState.merge({
    blockMap: updateBlockMapLinks(newBlocks, blockToBeMoved, targetBlock, insertionMode, isExperimentalTreeBlock),
    selectionBefore: contentState.getSelectionAfter(),
    selectionAfter: contentState.getSelectionAfter().merge({
      anchorKey: blockKey,
      focusKey: blockKey
    })
  });
};

module.exports = moveBlockInContentState;