@wordpress/block-library/build/list-item/hooks/use-merge.js

Block library for the WordPress editor.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = useMerge;
var _data = require("@wordpress/data");
var _blockEditor = require("@wordpress/block-editor");
var _useOutdentListItem = _interopRequireDefault(require("./use-outdent-list-item"));
/**
 * WordPress dependencies
 */

/**
 * Internal dependencies
 */

function useMerge(clientId, onMerge) {
  const registry = (0, _data.useRegistry)();
  const {
    getPreviousBlockClientId,
    getNextBlockClientId,
    getBlockOrder,
    getBlockRootClientId,
    getBlockName
  } = (0, _data.useSelect)(_blockEditor.store);
  const {
    mergeBlocks,
    moveBlocksToPosition
  } = (0, _data.useDispatch)(_blockEditor.store);
  const outdentListItem = (0, _useOutdentListItem.default)();
  function getTrailingId(id) {
    const order = getBlockOrder(id);
    if (!order.length) {
      return id;
    }
    return getTrailingId(order[order.length - 1]);
  }
  function getParentListItemId(id) {
    const listId = getBlockRootClientId(id);
    const parentListItemId = getBlockRootClientId(listId);
    if (!parentListItemId) {
      return;
    }
    if (getBlockName(parentListItemId) !== 'core/list-item') {
      return;
    }
    return parentListItemId;
  }

  /**
   * Return the next list item with respect to the given list item. If none,
   * return the next list item of the parent list item if it exists.
   *
   * @param {string} id A list item client ID.
   * @return {?string} The client ID of the next list item.
   */
  function _getNextId(id) {
    const next = getNextBlockClientId(id);
    if (next) {
      return next;
    }
    const parentListItemId = getParentListItemId(id);
    if (!parentListItemId) {
      return;
    }
    return _getNextId(parentListItemId);
  }

  /**
   * Given a client ID, return the client ID of the list item on the next
   * line, regardless of indentation level.
   *
   * @param {string} id The client ID of the current list item.
   * @return {?string} The client ID of the next list item.
   */
  function getNextId(id) {
    const order = getBlockOrder(id);

    // If the list item does not have a nested list, return the next list
    // item.
    if (!order.length) {
      return _getNextId(id);
    }

    // Get the first list item in the nested list.
    return getBlockOrder(order[0])[0];
  }
  return forward => {
    function mergeWithNested(clientIdA, clientIdB) {
      registry.batch(() => {
        // When merging a sub list item with a higher next list item, we
        // also need to move any nested list items. Check if there's a
        // listed list, and append its nested list items to the current
        // list.
        const [nestedListClientId] = getBlockOrder(clientIdB);
        if (nestedListClientId) {
          // If we are merging with the previous list item, and the
          // previous list item does not have nested list, move the
          // nested list to the previous list item.
          if (getPreviousBlockClientId(clientIdB) === clientIdA && !getBlockOrder(clientIdA).length) {
            moveBlocksToPosition([nestedListClientId], clientIdB, clientIdA);
          } else {
            moveBlocksToPosition(getBlockOrder(nestedListClientId), nestedListClientId, getBlockRootClientId(clientIdA));
          }
        }
        mergeBlocks(clientIdA, clientIdB);
      });
    }
    if (forward) {
      const nextBlockClientId = getNextId(clientId);
      if (!nextBlockClientId) {
        onMerge(forward);
        return;
      }
      if (getParentListItemId(nextBlockClientId)) {
        outdentListItem(nextBlockClientId);
      } else {
        mergeWithNested(clientId, nextBlockClientId);
      }
    } else {
      // Merging is only done from the top level. For lowel levels, the
      // list item is outdented instead.
      const previousBlockClientId = getPreviousBlockClientId(clientId);
      if (getParentListItemId(clientId)) {
        outdentListItem(clientId);
      } else if (previousBlockClientId) {
        const trailingId = getTrailingId(previousBlockClientId);
        mergeWithNested(trailingId, clientId);
      } else {
        onMerge(forward);
      }
    }
  };
}
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