Action

MMO.core.history · 1 symbol · generated 5 Oct 2026

class

class MMO.core.history.Action

	constructor(target, doFn, undoFn, state)	Create a new action
	execute()	Run the action, remembering what `doFn` returned so `undo` can restore it.
	undo()	Roll the action back.

Create a new action

constructor(target, doFn, undoFn, state)

target	`Object`	the targeted object
doFn	`Function`	MUST return an object with the property `data`. The value is passed to the undo action.
undoFn	`Function`	CAN return an object with the property `data`. The value is passed to the do action. if no data is returned, the first state is preserved and used in the do action.
state	`*`	a state to pass to the do action

Run the action, remembering what doFn returned so undo can restore it.

execute()

returns boolean false when the action had already run

Roll the action back. When undoFn returns a value it becomes the state a later execute replays, otherwise the original state is reused.

undo()

returns boolean false when the action was not in effect