Function: createUndoHistory()#

function createUndoHistory(root, options?): IRetreeUndoHistory;

Defined in: undoHistory.ts:135

Record every change under root into an undo/redo history built on attributable change records.

Parameters#

Returns#

IRetreeUndoHistory

An IRetreeUndoHistory controller.

Remarks#

The history subscribes to treeChanged on root and records each change batch as one step: everything flushed by one Retree.runTransaction is one step, and each discrete write outside a transaction is its own step (see RetreeUndoHistoryOptions.coalesce to merge discrete writes). undo() applies a step's inverse with Retree.applyInverse and redo() replays it with Retree.applyChanges; both emit normally — listeners and React re-render — without being recorded as new steps.

New writes recorded after an undo truncate the redo stack, exactly like a text editor. Steps beyond limit (default 100) drop oldest-first.

Call dispose() during teardown to remove the treeChanged subscription.

Example#

const project = Retree.root({ tasks: [{ title: "Docs", done: false }] });
const history = createUndoHistory(project);

project.tasks[0].done = true;
project.tasks.push({ title: "Tests", done: false });

history.undo(); // ✅ push undone; tasks has one entry
history.undo(); // ✅ done back to false
history.redo(); // ✅ done true again
history.dispose();