@wordpress/block-editor/build-module/store/reducer.js

Generic block editor.

/**
 * External dependencies
 */
import fastDeepEqual from 'fast-deep-equal/es6';

/**
 * WordPress dependencies
 */
import { pipe } from '@wordpress/compose';
import { combineReducers, select } from '@wordpress/data';
import deprecated from '@wordpress/deprecated';
import { store as blocksStore, privateApis as blocksPrivateApis } from '@wordpress/blocks';

/**
 * Internal dependencies
 */
import { PREFERENCES_DEFAULTS, SETTINGS_DEFAULTS } from './defaults';
import { insertAt, moveTo } from './array';
import { sectionRootClientIdKey } from './private-keys';
import { unlock } from '../lock-unlock';
const {
  isContentBlock
} = unlock(blocksPrivateApis);
const identity = x => x;

/**
 * Given an array of blocks, returns an object where each key is a nesting
 * context, the value of which is an array of block client IDs existing within
 * that nesting context.
 *
 * @param {Array}   blocks       Blocks to map.
 * @param {?string} rootClientId Assumed root client ID.
 *
 * @return {Object} Block order map object.
 */
function mapBlockOrder(blocks, rootClientId = '') {
  const result = new Map();
  const current = [];
  result.set(rootClientId, current);
  blocks.forEach(block => {
    const {
      clientId,
      innerBlocks
    } = block;
    current.push(clientId);
    mapBlockOrder(innerBlocks, clientId).forEach((order, subClientId) => {
      result.set(subClientId, order);
    });
  });
  return result;
}

/**
 * Given an array of blocks, returns an object where each key contains
 * the clientId of the block and the value is the parent of the block.
 *
 * @param {Array}   blocks       Blocks to map.
 * @param {?string} rootClientId Assumed root client ID.
 *
 * @return {Object} Block order map object.
 */
function mapBlockParents(blocks, rootClientId = '') {
  const result = [];
  const stack = [[rootClientId, blocks]];
  while (stack.length) {
    const [parent, currentBlocks] = stack.shift();
    currentBlocks.forEach(({
      innerBlocks,
      ...block
    }) => {
      result.push([block.clientId, parent]);
      if (innerBlocks?.length) {
        stack.push([block.clientId, innerBlocks]);
      }
    });
  }
  return result;
}

/**
 * Helper method to iterate through all blocks, recursing into inner blocks,
 * applying a transformation function to each one.
 * Returns a flattened object with the transformed blocks.
 *
 * @param {Array}    blocks    Blocks to flatten.
 * @param {Function} transform Transforming function to be applied to each block.
 *
 * @return {Array} Flattened object.
 */
function flattenBlocks(blocks, transform = identity) {
  const result = [];
  const stack = [...blocks];
  while (stack.length) {
    const {
      innerBlocks,
      ...block
    } = stack.shift();
    stack.push(...innerBlocks);
    result.push([block.clientId, transform(block)]);
  }
  return result;
}
function getFlattenedClientIds(blocks) {
  const result = {};
  const stack = [...blocks];
  while (stack.length) {
    const {
      innerBlocks,
      ...block
    } = stack.shift();
    stack.push(...innerBlocks);
    result[block.clientId] = true;
  }
  return result;
}

/**
 * Given an array of blocks, returns an object containing all blocks, without
 * attributes, recursing into inner blocks. Keys correspond to the block client
 * ID, the value of which is the attributes object.
 *
 * @param {Array} blocks Blocks to flatten.
 *
 * @return {Array} Flattened block attributes object.
 */
function getFlattenedBlocksWithoutAttributes(blocks) {
  return flattenBlocks(blocks, block => {
    const {
      attributes,
      ...restBlock
    } = block;
    return restBlock;
  });
}

/**
 * Given an array of blocks, returns an object containing all block attributes,
 * recursing into inner blocks. Keys correspond to the block client ID, the
 * value of which is the attributes object.
 *
 * @param {Array} blocks Blocks to flatten.
 *
 * @return {Array} Flattened block attributes object.
 */
function getFlattenedBlockAttributes(blocks) {
  return flattenBlocks(blocks, block => block.attributes);
}

/**
 * Returns true if the two object arguments have the same keys, or false
 * otherwise.
 *
 * @param {Object} a First object.
 * @param {Object} b Second object.
 *
 * @return {boolean} Whether the two objects have the same keys.
 */
export function hasSameKeys(a, b) {
  return fastDeepEqual(Object.keys(a), Object.keys(b));
}

/**
 * Returns true if, given the currently dispatching action and the previously
 * dispatched action, the two actions are updating the same block attribute, or
 * false otherwise.
 *
 * @param {Object} action     Currently dispatching action.
 * @param {Object} lastAction Previously dispatched action.
 *
 * @return {boolean} Whether actions are updating the same block attribute.
 */
export function isUpdatingSameBlockAttribute(action, lastAction) {
  return action.type === 'UPDATE_BLOCK_ATTRIBUTES' && lastAction !== undefined && lastAction.type === 'UPDATE_BLOCK_ATTRIBUTES' && fastDeepEqual(action.clientIds, lastAction.clientIds) && hasSameKeys(action.attributes, lastAction.attributes);
}
function updateBlockTreeForBlocks(state, blocks) {
  const treeToUpdate = state.tree;
  const stack = [...blocks];
  const flattenedBlocks = [...blocks];
  while (stack.length) {
    const block = stack.shift();
    stack.push(...block.innerBlocks);
    flattenedBlocks.push(...block.innerBlocks);
  }
  // Create objects before mutating them, that way it's always defined.
  for (const block of flattenedBlocks) {
    treeToUpdate.set(block.clientId, {});
  }
  for (const block of flattenedBlocks) {
    treeToUpdate.set(block.clientId, Object.assign(treeToUpdate.get(block.clientId), {
      ...state.byClientId.get(block.clientId),
      attributes: state.attributes.get(block.clientId),
      innerBlocks: block.innerBlocks.map(subBlock => treeToUpdate.get(subBlock.clientId))
    }));
  }
}
function updateParentInnerBlocksInTree(state, updatedClientIds, updateChildrenOfUpdatedClientIds = false) {
  const treeToUpdate = state.tree;
  const uncontrolledParents = new Set([]);
  const controlledParents = new Set();
  for (const clientId of updatedClientIds) {
    let current = updateChildrenOfUpdatedClientIds ? clientId : state.parents.get(clientId);
    do {
      if (state.controlledInnerBlocks[current]) {
        // Should stop on controlled blocks.
        // If we reach a controlled parent, break out of the loop.
        controlledParents.add(current);
        break;
      } else {
        // Else continue traversing up through parents.
        uncontrolledParents.add(current);
        current = state.parents.get(current);
      }
    } while (current !== undefined);
  }

  // To make sure the order of assignments doesn't matter,
  // we first create empty objects and mutates the inner blocks later.
  for (const clientId of uncontrolledParents) {
    treeToUpdate.set(clientId, {
      ...treeToUpdate.get(clientId)
    });
  }
  for (const clientId of uncontrolledParents) {
    treeToUpdate.get(clientId).innerBlocks = (state.order.get(clientId) || []).map(subClientId => treeToUpdate.get(subClientId));
  }

  // Controlled parent blocks, need a dedicated key for their inner blocks
  // to be used when doing getBlocks( controlledBlockClientId ).
  for (const clientId of controlledParents) {
    treeToUpdate.set('controlled||' + clientId, {
      innerBlocks: (state.order.get(clientId) || []).map(subClientId => treeToUpdate.get(subClientId))
    });
  }
}

/**
 * Higher-order reducer intended to compute full block objects key for each block in the post.
 * This is a denormalization to optimize the performance of the getBlock selectors and avoid
 * recomputing the block objects and avoid heavy memoization.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
const withBlockTree = reducer => (state = {}, action) => {
  const newState = reducer(state, action);
  if (newState === state) {
    return state;
  }
  newState.tree = state.tree ? state.tree : new Map();
  switch (action.type) {
    case 'RECEIVE_BLOCKS':
    case 'INSERT_BLOCKS':
      {
        newState.tree = new Map(newState.tree);
        updateBlockTreeForBlocks(newState, action.blocks);
        updateParentInnerBlocksInTree(newState, action.rootClientId ? [action.rootClientId] : [''], true);
        break;
      }
    case 'UPDATE_BLOCK':
      newState.tree = new Map(newState.tree);
      newState.tree.set(action.clientId, {
        ...newState.tree.get(action.clientId),
        ...newState.byClientId.get(action.clientId),
        attributes: newState.attributes.get(action.clientId)
      });
      updateParentInnerBlocksInTree(newState, [action.clientId], false);
      break;
    case 'SYNC_DERIVED_BLOCK_ATTRIBUTES':
    case 'UPDATE_BLOCK_ATTRIBUTES':
      {
        newState.tree = new Map(newState.tree);
        action.clientIds.forEach(clientId => {
          newState.tree.set(clientId, {
            ...newState.tree.get(clientId),
            attributes: newState.attributes.get(clientId)
          });
        });
        updateParentInnerBlocksInTree(newState, action.clientIds, false);
        break;
      }
    case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
      {
        const inserterClientIds = getFlattenedClientIds(action.blocks);
        newState.tree = new Map(newState.tree);
        action.replacedClientIds.forEach(clientId => {
          newState.tree.delete(clientId);
          // Controlled inner blocks are only removed
          // if the block doesn't move to another position
          // otherwise their content will be lost.
          if (!inserterClientIds[clientId]) {
            newState.tree.delete('controlled||' + clientId);
          }
        });
        updateBlockTreeForBlocks(newState, action.blocks);
        updateParentInnerBlocksInTree(newState, action.blocks.map(b => b.clientId), false);

        // If there are no replaced blocks, it means we're removing blocks so we need to update their parent.
        const parentsOfRemovedBlocks = [];
        for (const clientId of action.clientIds) {
          const parentId = state.parents.get(clientId);
          if (parentId !== undefined && (parentId === '' || newState.byClientId.get(parentId))) {
            parentsOfRemovedBlocks.push(parentId);
          }
        }
        updateParentInnerBlocksInTree(newState, parentsOfRemovedBlocks, true);
        break;
      }
    case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
      const parentsOfRemovedBlocks = [];
      for (const clientId of action.clientIds) {
        const parentId = state.parents.get(clientId);
        if (parentId !== undefined && (parentId === '' || newState.byClientId.get(parentId))) {
          parentsOfRemovedBlocks.push(parentId);
        }
      }
      newState.tree = new Map(newState.tree);
      action.removedClientIds.forEach(clientId => {
        newState.tree.delete(clientId);
        newState.tree.delete('controlled||' + clientId);
      });
      updateParentInnerBlocksInTree(newState, parentsOfRemovedBlocks, true);
      break;
    case 'MOVE_BLOCKS_TO_POSITION':
      {
        const updatedBlockUids = [];
        if (action.fromRootClientId) {
          updatedBlockUids.push(action.fromRootClientId);
        } else {
          updatedBlockUids.push('');
        }
        if (action.toRootClientId) {
          updatedBlockUids.push(action.toRootClientId);
        }
        newState.tree = new Map(newState.tree);
        updateParentInnerBlocksInTree(newState, updatedBlockUids, true);
        break;
      }
    case 'MOVE_BLOCKS_UP':
    case 'MOVE_BLOCKS_DOWN':
      {
        const updatedBlockUids = [action.rootClientId ? action.rootClientId : ''];
        newState.tree = new Map(newState.tree);
        updateParentInnerBlocksInTree(newState, updatedBlockUids, true);
        break;
      }
    case 'SAVE_REUSABLE_BLOCK_SUCCESS':
      {
        const updatedBlockUids = [];
        newState.attributes.forEach((attributes, clientId) => {
          if (newState.byClientId.get(clientId).name === 'core/block' && attributes.ref === action.updatedId) {
            updatedBlockUids.push(clientId);
          }
        });
        newState.tree = new Map(newState.tree);
        updatedBlockUids.forEach(clientId => {
          newState.tree.set(clientId, {
            ...newState.byClientId.get(clientId),
            attributes: newState.attributes.get(clientId),
            innerBlocks: newState.tree.get(clientId).innerBlocks
          });
        });
        updateParentInnerBlocksInTree(newState, updatedBlockUids, false);
      }
  }
  return newState;
};

/**
 * Higher-order reducer intended to augment the blocks reducer, assigning an
 * `isPersistentChange` property value corresponding to whether a change in
 * state can be considered as persistent. All changes are considered persistent
 * except when updating the same block attribute as in the previous action.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
function withPersistentBlockChange(reducer) {
  let lastAction;
  let markNextChangeAsNotPersistent = false;
  let explicitPersistent;
  return (state, action) => {
    let nextState = reducer(state, action);
    let nextIsPersistentChange;
    if (action.type === 'SET_EXPLICIT_PERSISTENT') {
      var _state$isPersistentCh;
      explicitPersistent = action.isPersistentChange;
      nextIsPersistentChange = (_state$isPersistentCh = state.isPersistentChange) !== null && _state$isPersistentCh !== void 0 ? _state$isPersistentCh : true;
    }
    if (explicitPersistent !== undefined) {
      nextIsPersistentChange = explicitPersistent;
      return nextIsPersistentChange === nextState.isPersistentChange ? nextState : {
        ...nextState,
        isPersistentChange: nextIsPersistentChange
      };
    }
    const isExplicitPersistentChange = action.type === 'MARK_LAST_CHANGE_AS_PERSISTENT' || markNextChangeAsNotPersistent;

    // Defer to previous state value (or default) unless changing or
    // explicitly marking as persistent.
    if (state === nextState && !isExplicitPersistentChange) {
      var _state$isPersistentCh2;
      markNextChangeAsNotPersistent = action.type === 'MARK_NEXT_CHANGE_AS_NOT_PERSISTENT';
      nextIsPersistentChange = (_state$isPersistentCh2 = state?.isPersistentChange) !== null && _state$isPersistentCh2 !== void 0 ? _state$isPersistentCh2 : true;
      if (state.isPersistentChange === nextIsPersistentChange) {
        return state;
      }
      return {
        ...nextState,
        isPersistentChange: nextIsPersistentChange
      };
    }
    nextState = {
      ...nextState,
      isPersistentChange: isExplicitPersistentChange ? !markNextChangeAsNotPersistent : !isUpdatingSameBlockAttribute(action, lastAction)
    };

    // In comparing against the previous action, consider only those which
    // would have qualified as one which would have been ignored or not
    // have resulted in a changed state.
    lastAction = action;
    markNextChangeAsNotPersistent = action.type === 'MARK_NEXT_CHANGE_AS_NOT_PERSISTENT';
    return nextState;
  };
}

/**
 * Higher-order reducer intended to augment the blocks reducer, assigning an
 * `isIgnoredChange` property value corresponding to whether a change in state
 * can be considered as ignored. A change is considered ignored when the result
 * of an action not incurred by direct user interaction.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
function withIgnoredBlockChange(reducer) {
  /**
   * Set of action types for which a blocks state change should be ignored.
   *
   * @type {Set}
   */
  const IGNORED_ACTION_TYPES = new Set(['RECEIVE_BLOCKS']);
  return (state, action) => {
    const nextState = reducer(state, action);
    if (nextState !== state) {
      nextState.isIgnoredChange = IGNORED_ACTION_TYPES.has(action.type);
    }
    return nextState;
  };
}

/**
 * Higher-order reducer targeting the combined blocks reducer, augmenting
 * block client IDs in remove action to include cascade of inner blocks.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
const withInnerBlocksRemoveCascade = reducer => (state, action) => {
  // Gets all children which need to be removed.
  const getAllChildren = clientIds => {
    let result = clientIds;
    for (let i = 0; i < result.length; i++) {
      if (!state.order.get(result[i]) || action.keepControlledInnerBlocks && action.keepControlledInnerBlocks[result[i]]) {
        continue;
      }
      if (result === clientIds) {
        result = [...result];
      }
      result.push(...state.order.get(result[i]));
    }
    return result;
  };
  if (state) {
    switch (action.type) {
      case 'REMOVE_BLOCKS':
        action = {
          ...action,
          type: 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN',
          removedClientIds: getAllChildren(action.clientIds)
        };
        break;
      case 'REPLACE_BLOCKS':
        action = {
          ...action,
          type: 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN',
          replacedClientIds: getAllChildren(action.clientIds)
        };
        break;
    }
  }
  return reducer(state, action);
};

/**
 * Higher-order reducer which targets the combined blocks reducer and handles
 * the `RESET_BLOCKS` action. When dispatched, this action will replace all
 * blocks that exist in the post, leaving blocks that exist only in state (e.g.
 * reusable blocks and blocks controlled by inner blocks controllers) alone.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
const withBlockReset = reducer => (state, action) => {
  if (action.type === 'RESET_BLOCKS') {
    const newState = {
      ...state,
      byClientId: new Map(getFlattenedBlocksWithoutAttributes(action.blocks)),
      attributes: new Map(getFlattenedBlockAttributes(action.blocks)),
      order: mapBlockOrder(action.blocks),
      parents: new Map(mapBlockParents(action.blocks)),
      controlledInnerBlocks: {}
    };
    newState.tree = new Map(state?.tree);
    updateBlockTreeForBlocks(newState, action.blocks);
    newState.tree.set('', {
      innerBlocks: action.blocks.map(subBlock => newState.tree.get(subBlock.clientId))
    });
    return newState;
  }
  return reducer(state, action);
};

/**
 * Higher-order reducer which targets the combined blocks reducer and handles
 * the `REPLACE_INNER_BLOCKS` action. When dispatched, this action the state
 * should become equivalent to the execution of a `REMOVE_BLOCKS` action
 * containing all the child's of the root block followed by the execution of
 * `INSERT_BLOCKS` with the new blocks.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
const withReplaceInnerBlocks = reducer => (state, action) => {
  if (action.type !== 'REPLACE_INNER_BLOCKS') {
    return reducer(state, action);
  }

  // Finds every nested inner block controller. We must check the action blocks
  // and not just the block parent state because some inner block controllers
  // should be deleted if specified, whereas others should not be deleted. If
  // a controlled should not be deleted, then we need to avoid deleting its
  // inner blocks from the block state because its inner blocks will not be
  // attached to the block in the action.
  const nestedControllers = {};
  if (Object.keys(state.controlledInnerBlocks).length) {
    const stack = [...action.blocks];
    while (stack.length) {
      const {
        innerBlocks,
        ...block
      } = stack.shift();
      stack.push(...innerBlocks);
      if (!!state.controlledInnerBlocks[block.clientId]) {
        nestedControllers[block.clientId] = true;
      }
    }
  }

  // The `keepControlledInnerBlocks` prop will keep the inner blocks of the
  // marked block in the block state so that they can be reattached to the
  // marked block when we re-insert everything a few lines below.
  let stateAfterBlocksRemoval = state;
  if (state.order.get(action.rootClientId)) {
    stateAfterBlocksRemoval = reducer(stateAfterBlocksRemoval, {
      type: 'REMOVE_BLOCKS',
      keepControlledInnerBlocks: nestedControllers,
      clientIds: state.order.get(action.rootClientId)
    });
  }
  let stateAfterInsert = stateAfterBlocksRemoval;
  if (action.blocks.length) {
    stateAfterInsert = reducer(stateAfterInsert, {
      ...action,
      type: 'INSERT_BLOCKS',
      index: 0
    });

    // We need to re-attach the controlled inner blocks to the blocks tree and
    // preserve their block order. Otherwise, an inner block controller's blocks
    // will be deleted entirely from its entity.
    const stateAfterInsertOrder = new Map(stateAfterInsert.order);
    Object.keys(nestedControllers).forEach(key => {
      if (state.order.get(key)) {
        stateAfterInsertOrder.set(key, state.order.get(key));
      }
    });
    stateAfterInsert.order = stateAfterInsertOrder;
    stateAfterInsert.tree = new Map(stateAfterInsert.tree);
    Object.keys(nestedControllers).forEach(_key => {
      const key = `controlled||${_key}`;
      if (state.tree.has(key)) {
        stateAfterInsert.tree.set(key, state.tree.get(key));
      }
    });
  }
  return stateAfterInsert;
};

/**
 * Higher-order reducer which targets the combined blocks reducer and handles
 * the `SAVE_REUSABLE_BLOCK_SUCCESS` action. This action can't be handled by
 * regular reducers and needs a higher-order reducer since it needs access to
 * both `byClientId` and `attributes` simultaneously.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
const withSaveReusableBlock = reducer => (state, action) => {
  if (state && action.type === 'SAVE_REUSABLE_BLOCK_SUCCESS') {
    const {
      id,
      updatedId
    } = action;

    // If a temporary reusable block is saved, we swap the temporary id with the final one.
    if (id === updatedId) {
      return state;
    }
    state = {
      ...state
    };
    state.attributes = new Map(state.attributes);
    state.attributes.forEach((attributes, clientId) => {
      const {
        name
      } = state.byClientId.get(clientId);
      if (name === 'core/block' && attributes.ref === id) {
        state.attributes.set(clientId, {
          ...attributes,
          ref: updatedId
        });
      }
    });
  }
  return reducer(state, action);
};
/**
 * Higher-order reducer which removes blocks from state when switching parent block controlled state.
 *
 * @param {Function} reducer Original reducer function.
 *
 * @return {Function} Enhanced reducer function.
 */
const withResetControlledBlocks = reducer => (state, action) => {
  if (action.type === 'SET_HAS_CONTROLLED_INNER_BLOCKS') {
    // when switching a block from controlled to uncontrolled or inverse,
    // we need to remove its content first.
    const tempState = reducer(state, {
      type: 'REPLACE_INNER_BLOCKS',
      rootClientId: action.clientId,
      blocks: []
    });
    return reducer(tempState, action);
  }
  return reducer(state, action);
};

/**
 * Reducer returning the blocks state.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {Object} Updated state.
 */
export const blocks = pipe(combineReducers, withSaveReusableBlock,
// Needs to be before withBlockCache.
withBlockTree,
// Needs to be before withInnerBlocksRemoveCascade.
withInnerBlocksRemoveCascade, withReplaceInnerBlocks,
// Needs to be after withInnerBlocksRemoveCascade.
withBlockReset, withPersistentBlockChange, withIgnoredBlockChange, withResetControlledBlocks)({
  // The state is using a Map instead of a plain object for performance reasons.
  // You can run the "./test/performance.js" unit test to check the impact
  // code changes can have on this reducer.
  byClientId(state = new Map(), action) {
    switch (action.type) {
      case 'RECEIVE_BLOCKS':
      case 'INSERT_BLOCKS':
        {
          const newState = new Map(state);
          getFlattenedBlocksWithoutAttributes(action.blocks).forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'UPDATE_BLOCK':
        {
          // Ignore updates if block isn't known.
          if (!state.has(action.clientId)) {
            return state;
          }

          // Do nothing if only attributes change.
          const {
            attributes,
            ...changes
          } = action.updates;
          if (Object.values(changes).length === 0) {
            return state;
          }
          const newState = new Map(state);
          newState.set(action.clientId, {
            ...state.get(action.clientId),
            ...changes
          });
          return newState;
        }
      case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          if (!action.blocks) {
            return state;
          }
          const newState = new Map(state);
          action.replacedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          getFlattenedBlocksWithoutAttributes(action.blocks).forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          const newState = new Map(state);
          action.removedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          return newState;
        }
    }
    return state;
  },
  // The state is using a Map instead of a plain object for performance reasons.
  // You can run the "./test/performance.js" unit test to check the impact
  // code changes can have on this reducer.
  attributes(state = new Map(), action) {
    switch (action.type) {
      case 'RECEIVE_BLOCKS':
      case 'INSERT_BLOCKS':
        {
          const newState = new Map(state);
          getFlattenedBlockAttributes(action.blocks).forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'UPDATE_BLOCK':
        {
          // Ignore updates if block isn't known or there are no attribute changes.
          if (!state.get(action.clientId) || !action.updates.attributes) {
            return state;
          }
          const newState = new Map(state);
          newState.set(action.clientId, {
            ...state.get(action.clientId),
            ...action.updates.attributes
          });
          return newState;
        }
      case 'SYNC_DERIVED_BLOCK_ATTRIBUTES':
      case 'UPDATE_BLOCK_ATTRIBUTES':
        {
          // Avoid a state change if none of the block IDs are known.
          if (action.clientIds.every(id => !state.get(id))) {
            return state;
          }
          let hasChange = false;
          const newState = new Map(state);
          for (const clientId of action.clientIds) {
            var _action$attributes;
            const updatedAttributeEntries = Object.entries(action.uniqueByBlock ? action.attributes[clientId] : (_action$attributes = action.attributes) !== null && _action$attributes !== void 0 ? _action$attributes : {});
            if (updatedAttributeEntries.length === 0) {
              continue;
            }
            let hasUpdatedAttributes = false;
            const existingAttributes = state.get(clientId);
            const newAttributes = {};
            updatedAttributeEntries.forEach(([key, value]) => {
              if (existingAttributes[key] !== value) {
                hasUpdatedAttributes = true;
                newAttributes[key] = value;
              }
            });
            hasChange = hasChange || hasUpdatedAttributes;
            if (hasUpdatedAttributes) {
              newState.set(clientId, {
                ...existingAttributes,
                ...newAttributes
              });
            }
          }
          return hasChange ? newState : state;
        }
      case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          if (!action.blocks) {
            return state;
          }
          const newState = new Map(state);
          action.replacedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          getFlattenedBlockAttributes(action.blocks).forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          const newState = new Map(state);
          action.removedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          return newState;
        }
    }
    return state;
  },
  // The state is using a Map instead of a plain object for performance reasons.
  // You can run the "./test/performance.js" unit test to check the impact
  // code changes can have on this reducer.
  order(state = new Map(), action) {
    switch (action.type) {
      case 'RECEIVE_BLOCKS':
        {
          var _state$get;
          const blockOrder = mapBlockOrder(action.blocks);
          const newState = new Map(state);
          blockOrder.forEach((order, clientId) => {
            if (clientId !== '') {
              newState.set(clientId, order);
            }
          });
          newState.set('', ((_state$get = state.get('')) !== null && _state$get !== void 0 ? _state$get : []).concat(blockOrder['']));
          return newState;
        }
      case 'INSERT_BLOCKS':
        {
          const {
            rootClientId = ''
          } = action;
          const subState = state.get(rootClientId) || [];
          const mappedBlocks = mapBlockOrder(action.blocks, rootClientId);
          const {
            index = subState.length
          } = action;
          const newState = new Map(state);
          mappedBlocks.forEach((order, clientId) => {
            newState.set(clientId, order);
          });
          newState.set(rootClientId, insertAt(subState, mappedBlocks.get(rootClientId), index));
          return newState;
        }
      case 'MOVE_BLOCKS_TO_POSITION':
        {
          var _state$get$filter;
          const {
            fromRootClientId = '',
            toRootClientId = '',
            clientIds
          } = action;
          const {
            index = state.get(toRootClientId).length
          } = action;

          // Moving inside the same parent block.
          if (fromRootClientId === toRootClientId) {
            const subState = state.get(toRootClientId);
            const fromIndex = subState.indexOf(clientIds[0]);
            const newState = new Map(state);
            newState.set(toRootClientId, moveTo(state.get(toRootClientId), fromIndex, index, clientIds.length));
            return newState;
          }

          // Moving from a parent block to another.
          const newState = new Map(state);
          newState.set(fromRootClientId, (_state$get$filter = state.get(fromRootClientId)?.filter(id => !clientIds.includes(id))) !== null && _state$get$filter !== void 0 ? _state$get$filter : []);
          newState.set(toRootClientId, insertAt(state.get(toRootClientId), clientIds, index));
          return newState;
        }
      case 'MOVE_BLOCKS_UP':
        {
          const {
            clientIds,
            rootClientId = ''
          } = action;
          const firstClientId = clientIds[0];
          const subState = state.get(rootClientId);
          if (!subState.length || firstClientId === subState[0]) {
            return state;
          }
          const firstIndex = subState.indexOf(firstClientId);
          const newState = new Map(state);
          newState.set(rootClientId, moveTo(subState, firstIndex, firstIndex - 1, clientIds.length));
          return newState;
        }
      case 'MOVE_BLOCKS_DOWN':
        {
          const {
            clientIds,
            rootClientId = ''
          } = action;
          const firstClientId = clientIds[0];
          const lastClientId = clientIds[clientIds.length - 1];
          const subState = state.get(rootClientId);
          if (!subState.length || lastClientId === subState[subState.length - 1]) {
            return state;
          }
          const firstIndex = subState.indexOf(firstClientId);
          const newState = new Map(state);
          newState.set(rootClientId, moveTo(subState, firstIndex, firstIndex + 1, clientIds.length));
          return newState;
        }
      case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          const {
            clientIds
          } = action;
          if (!action.blocks) {
            return state;
          }
          const mappedBlocks = mapBlockOrder(action.blocks);
          const newState = new Map(state);
          action.replacedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          mappedBlocks.forEach((order, clientId) => {
            if (clientId !== '') {
              newState.set(clientId, order);
            }
          });
          newState.forEach((order, clientId) => {
            const newSubOrder = Object.values(order).reduce((result, subClientId) => {
              if (subClientId === clientIds[0]) {
                return [...result, ...mappedBlocks.get('')];
              }
              if (clientIds.indexOf(subClientId) === -1) {
                result.push(subClientId);
              }
              return result;
            }, []);
            newState.set(clientId, newSubOrder);
          });
          return newState;
        }
      case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          const newState = new Map(state);
          // Remove inner block ordering for removed blocks.
          action.removedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          newState.forEach((order, clientId) => {
            var _order$filter;
            const newSubOrder = (_order$filter = order?.filter(id => !action.removedClientIds.includes(id))) !== null && _order$filter !== void 0 ? _order$filter : [];
            if (newSubOrder.length !== order.length) {
              newState.set(clientId, newSubOrder);
            }
          });
          return newState;
        }
    }
    return state;
  },
  // While technically redundant data as the inverse of `order`, it serves as
  // an optimization for the selectors which derive the ancestry of a block.
  parents(state = new Map(), action) {
    switch (action.type) {
      case 'RECEIVE_BLOCKS':
        {
          const newState = new Map(state);
          mapBlockParents(action.blocks).forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'INSERT_BLOCKS':
        {
          const newState = new Map(state);
          mapBlockParents(action.blocks, action.rootClientId || '').forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'MOVE_BLOCKS_TO_POSITION':
        {
          const newState = new Map(state);
          action.clientIds.forEach(id => {
            newState.set(id, action.toRootClientId || '');
          });
          return newState;
        }
      case 'REPLACE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          const newState = new Map(state);
          action.replacedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          mapBlockParents(action.blocks, state.get(action.clientIds[0])).forEach(([key, value]) => {
            newState.set(key, value);
          });
          return newState;
        }
      case 'REMOVE_BLOCKS_AUGMENTED_WITH_CHILDREN':
        {
          const newState = new Map(state);
          action.removedClientIds.forEach(clientId => {
            newState.delete(clientId);
          });
          return newState;
        }
    }
    return state;
  },
  controlledInnerBlocks(state = {}, {
    type,
    clientId,
    hasControlledInnerBlocks
  }) {
    if (type === 'SET_HAS_CONTROLLED_INNER_BLOCKS') {
      return {
        ...state,
        [clientId]: hasControlledInnerBlocks
      };
    }
    return state;
  }
});

/**
 * Reducer returning visibility status of block interface.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function isBlockInterfaceHidden(state = false, action) {
  switch (action.type) {
    case 'HIDE_BLOCK_INTERFACE':
      return true;
    case 'SHOW_BLOCK_INTERFACE':
      return false;
  }
  return state;
}

/**
 * Reducer returning typing state.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function isTyping(state = false, action) {
  switch (action.type) {
    case 'START_TYPING':
      return true;
    case 'STOP_TYPING':
      return false;
  }
  return state;
}

/**
 * Reducer returning dragging state. It is possible for a user to be dragging
 * data from outside of the editor, so this state is separate from `draggedBlocks`.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function isDragging(state = false, action) {
  switch (action.type) {
    case 'START_DRAGGING':
      return true;
    case 'STOP_DRAGGING':
      return false;
  }
  return state;
}

/**
 * Reducer returning dragged block client id.
 *
 * @param {string[]} state  Current state.
 * @param {Object}   action Dispatched action.
 *
 * @return {string[]} Updated state.
 */
export function draggedBlocks(state = [], action) {
  switch (action.type) {
    case 'START_DRAGGING_BLOCKS':
      return action.clientIds;
    case 'STOP_DRAGGING_BLOCKS':
      return [];
  }
  return state;
}

/**
 * Reducer tracking the visible blocks.
 *
 * @param {Record<string,boolean>} state  Current state.
 * @param {Object}                 action Dispatched action.
 *
 * @return {Record<string,boolean>} Block visibility.
 */
export function blockVisibility(state = {}, action) {
  if (action.type === 'SET_BLOCK_VISIBILITY') {
    return {
      ...state,
      ...action.updates
    };
  }
  return state;
}

/**
 * Internal helper reducer for selectionStart and selectionEnd. Can hold a block
 * selection, represented by an object with property clientId.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {Object} Updated state.
 */
function selectionHelper(state = {}, action) {
  switch (action.type) {
    case 'CLEAR_SELECTED_BLOCK':
      {
        if (state.clientId) {
          return {};
        }
        return state;
      }
    case 'SELECT_BLOCK':
      if (action.clientId === state.clientId) {
        return state;
      }
      return {
        clientId: action.clientId
      };
    case 'REPLACE_INNER_BLOCKS':
    case 'INSERT_BLOCKS':
      {
        if (!action.updateSelection || !action.blocks.length) {
          return state;
        }
        return {
          clientId: action.blocks[0].clientId
        };
      }
    case 'REMOVE_BLOCKS':
      if (!action.clientIds || !action.clientIds.length || action.clientIds.indexOf(state.clientId) === -1) {
        return state;
      }
      return {};
    case 'REPLACE_BLOCKS':
      {
        if (action.clientIds.indexOf(state.clientId) === -1) {
          return state;
        }
        const blockToSelect = action.blocks[action.indexToSelect] || action.blocks[action.blocks.length - 1];
        if (!blockToSelect) {
          return {};
        }
        if (blockToSelect.clientId === state.clientId) {
          return state;
        }
        return {
          clientId: blockToSelect.clientId
        };
      }
  }
  return state;
}

/**
 * Reducer returning the selection state.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function selection(state = {}, action) {
  switch (action.type) {
    case 'SELECTION_CHANGE':
      if (action.clientId) {
        return {
          selectionStart: {
            clientId: action.clientId,
            attributeKey: action.attributeKey,
            offset: action.startOffset
          },
          selectionEnd: {
            clientId: action.clientId,
            attributeKey: action.attributeKey,
            offset: action.endOffset
          }
        };
      }
      return {
        selectionStart: action.start || state.selectionStart,
        selectionEnd: action.end || state.selectionEnd
      };
    case 'RESET_SELECTION':
      const {
        selectionStart,
        selectionEnd
      } = action;
      return {
        selectionStart,
        selectionEnd
      };
    case 'MULTI_SELECT':
      const {
        start,
        end
      } = action;
      if (start === state.selectionStart?.clientId && end === state.selectionEnd?.clientId) {
        return state;
      }
      return {
        selectionStart: {
          clientId: start
        },
        selectionEnd: {
          clientId: end
        }
      };
    case 'RESET_BLOCKS':
      const startClientId = state?.selectionStart?.clientId;
      const endClientId = state?.selectionEnd?.clientId;

      // Do nothing if there's no selected block.
      if (!startClientId && !endClientId) {
        return state;
      }

      // If the start of the selection won't exist after reset, remove selection.
      if (!action.blocks.some(block => block.clientId === startClientId)) {
        return {
          selectionStart: {},
          selectionEnd: {}
        };
      }

      // If the end of the selection won't exist after reset, collapse selection.
      if (!action.blocks.some(block => block.clientId === endClientId)) {
        return {
          ...state,
          selectionEnd: state.selectionStart
        };
      }
  }
  const selectionStart = selectionHelper(state.selectionStart, action);
  const selectionEnd = selectionHelper(state.selectionEnd, action);
  if (selectionStart === state.selectionStart && selectionEnd === state.selectionEnd) {
    return state;
  }
  return {
    selectionStart,
    selectionEnd
  };
}

/**
 * Reducer returning whether the user is multi-selecting.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function isMultiSelecting(state = false, action) {
  switch (action.type) {
    case 'START_MULTI_SELECT':
      return true;
    case 'STOP_MULTI_SELECT':
      return false;
  }
  return state;
}

/**
 * Reducer returning whether selection is enabled.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function isSelectionEnabled(state = true, action) {
  switch (action.type) {
    case 'TOGGLE_SELECTION':
      return action.isSelectionEnabled;
  }
  return state;
}

/**
 * Reducer returning the data needed to display a prompt when certain blocks
 * are removed, or `false` if no such prompt is requested.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {Object|false} Data for removal prompt display, if any.
 */
function removalPromptData(state = false, action) {
  switch (action.type) {
    case 'DISPLAY_BLOCK_REMOVAL_PROMPT':
      const {
        clientIds,
        selectPrevious,
        message
      } = action;
      return {
        clientIds,
        selectPrevious,
        message
      };
    case 'CLEAR_BLOCK_REMOVAL_PROMPT':
      return false;
  }
  return state;
}

/**
 * Reducer returning any rules that a block editor may provide in order to
 * prevent a user from accidentally removing certain blocks. These rules are
 * then used to display a confirmation prompt to the user. For instance, in the
 * Site Editor, the Query Loop block is important enough to warrant such
 * confirmation.
 *
 * The data is a record whose keys are block types (e.g. 'core/query') and
 * whose values are the explanation to be shown to users (e.g. 'Query Loop
 * displays a list of posts or pages.').
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {Record<string,string>} Updated state.
 */
function blockRemovalRules(state = false, action) {
  switch (action.type) {
    case 'SET_BLOCK_REMOVAL_RULES':
      return action.rules;
  }
  return state;
}

/**
 * Reducer returning the initial block selection.
 *
 * Currently this in only used to restore the selection after block deletion and
 * pasting new content.This reducer should eventually be removed in favour of setting
 * selection directly.
 *
 * @param {boolean} state  Current state.
 * @param {Object}  action Dispatched action.
 *
 * @return {number|null} Initial position: 0, -1 or null.
 */
export function initialPosition(state = null, action) {
  if (action.type === 'REPLACE_BLOCKS' && action.initialPosition !== undefined) {
    return action.initialPosition;
  } else if (['MULTI_SELECT', 'SELECT_BLOCK', 'RESET_SELECTION', 'INSERT_BLOCKS', 'REPLACE_INNER_BLOCKS'].includes(action.type)) {
    return action.initialPosition;
  }
  return state;
}
export function blocksMode(state = {}, action) {
  if (action.type === 'TOGGLE_BLOCK_MODE') {
    const {
      clientId
    } = action;
    return {
      ...state,
      [clientId]: state[clientId] && state[clientId] === 'html' ? 'visual' : 'html'
    };
  }
  return state;
}

/**
 * Reducer returning the block insertion point visibility, either null if there
 * is not an explicit insertion point assigned, or an object of its `index` and
 * `rootClientId`.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {Object} Updated state.
 */
export function insertionCue(state = null, action) {
  switch (action.type) {
    case 'SHOW_INSERTION_POINT':
      {
        const {
          rootClientId,
          index,
          __unstableWithInserter,
          operation,
          nearestSide
        } = action;
        const nextState = {
          rootClientId,
          index,
          __unstableWithInserter,
          operation,
          nearestSide
        };

        // Bail out updates if the states are the same.
        return fastDeepEqual(state, nextState) ? state : nextState;
      }
    case 'HIDE_INSERTION_POINT':
      return null;
  }
  return state;
}

/**
 * Reducer returning whether the post blocks match the defined template or not.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {boolean} Updated state.
 */
export function template(state = {
  isValid: true
}, action) {
  switch (action.type) {
    case 'SET_TEMPLATE_VALIDITY':
      return {
        ...state,
        isValid: action.isValid
      };
  }
  return state;
}

/**
 * Reducer returning the editor setting.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {Object} Updated state.
 */
export function settings(state = SETTINGS_DEFAULTS, action) {
  switch (action.type) {
    case 'UPDATE_SETTINGS':
      {
        const updatedSettings = action.reset ? {
          ...SETTINGS_DEFAULTS,
          ...action.settings
        } : {
          ...state,
          ...action.settings
        };
        Object.defineProperty(updatedSettings, '__unstableIsPreviewMode', {
          get() {
            deprecated('__unstableIsPreviewMode', {
              since: '6.8',
              alternative: 'isPreviewMode'
            });
            return this.isPreviewMode;
          }
        });
        return updatedSettings;
      }
  }
  return state;
}

/**
 * Reducer returning the user preferences.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {string} Updated state.
 */
export function preferences(state = PREFERENCES_DEFAULTS, action) {
  switch (action.type) {
    case 'INSERT_BLOCKS':
    case 'REPLACE_BLOCKS':
      {
        const nextInsertUsage = action.blocks.reduce((prevUsage, block) => {
          const {
            attributes,
            name: blockName
          } = block;
          let id = blockName;
          // If a block variation match is found change the name to be the same with the
          // one that is used for block variations in the Inserter (`getItemFromVariation`).
          const match = select(blocksStore).getActiveBlockVariation(blockName, attributes);
          if (match?.name) {
            id += '/' + match.name;
          }
          if (blockName === 'core/block') {
            id += '/' + attributes.ref;
          }
          return {
            ...prevUsage,
            [id]: {
              time: action.time,
              count: prevUsage[id] ? prevUsage[id].count + 1 : 1
            }
          };
        }, state.insertUsage);
        return {
          ...state,
          insertUsage: nextInsertUsage
        };
      }
  }
  return state;
}

/**
 * Reducer returning an object where each key is a block client ID, its value
 * representing the settings for its nested blocks.
 *
 * @param {Object} state  Current state.
 * @param {Object} action Dispatched action.
 *
 * @return {Object} Updated state.
 */
export const blockListSettings = (state = {}, action) => {
  switch (action.type) {
    // Even if the replaced blocks have the same client ID, our logic
    // should correct the state.
    case 'REPLACE_BLOCKS':
    case 'REMOVE_BLOCKS':
      {
        return Object.fromEntries(Object.entries(state).filter(([id]) => !action.clientIds.includes(id)));