undoable()

undoable(execute, undo): UndoableCommand

Creates an undoable command from an execute/undo pair.

---

Parameters

execute: Command

The action to perform

undo: Command

The action that reverses execute

---

Returns: UndoableCommand

An UndoableCommand

---

Since

2.4.0

---

Example

const items: string[] = [];

const addItem = (item: string) => undoable(
  () => items.push(item),
  () => items.pop(),
);

const cmd = addItem("hello");
cmd.execute(); // items = ["hello"]
cmd.undo();    // items = []

UndoableCommand

Interface

An UndoableCommand pairs an execute action with its inverse. Replaces the GoF Command interface + ConcreteCommand classes.

---

Since

2.4.0

---

Properties

execute: Command

undo

readonly undo: Command

Command()

Type

Command = () => void

A Command is a thunk - a deferred action with no arguments. In FP, this IS the pattern: a function is already a reifiable value.

---

Returns: void

---

Since

2.4.0