@ckeditor/ckeditor5-undo/src/redocommand.js

Undo feature for CKEditor 5.

/**
 * @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */
/**
 * @module undo/redocommand
 */
import { UndoRedoBaseCommand } from './basecommand.js';
/**
 * The redo command stores {@link module:engine/model/batch~Batch batches} that were used to undo a batch by
 * {@link module:undo/undocommand~UndoCommand}. It is able to redo a previously undone batch by reversing the undoing
 * batches created by `UndoCommand`. The reversed batch is transformed by all the batches from
 * {@link module:engine/model/document~ModelDocument#history history} that happened after the reversed undo batch.
 *
 * The redo command also takes care of restoring the {@link module:engine/model/document~ModelDocument#selection document selection}.
 */
export class RedoCommand extends UndoRedoBaseCommand {
    /**
     * Executes the command. This method reverts the last {@link module:engine/model/batch~Batch batch} added to
     * the command's stack, applies the reverted and transformed version on the
     * {@link module:engine/model/document~ModelDocument document} and removes the batch from the stack.
     * Then, it restores the {@link module:engine/model/document~ModelDocument#selection document selection}.
     *
     * @fires execute
     */
    execute() {
        const item = this._stack.pop();
        const redoingBatch = this.editor.model.createBatch({ isUndo: true });
        // All changes have to be done in one `enqueueChange` callback so other listeners will not step between consecutive
        // operations, or won't do changes to the document before selection is properly restored.
        this.editor.model.enqueueChange(redoingBatch, () => {
            const lastOperation = item.batch.operations[item.batch.operations.length - 1];
            const nextBaseVersion = lastOperation.baseVersion + 1;
            const operations = this.editor.model.document.history.getOperations(nextBaseVersion);
            this._restoreSelection(item.selection.ranges, item.selection.isBackward, operations);
            this._undo(item.batch, redoingBatch);
        });
        // Firing `revert` event after the change block to make sure that it includes all changes from post-fixers
        // and make sure that the selection is "stabilized" (the selection range is saved after undo is executed and then
        // restored on redo, so it is important that the selection range is saved after post-fixers are done).
        this.fire('revert', item.batch, redoingBatch);
        this.refresh();
    }
}