Skip to main content

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