History

import { History } from 'pixi-silk/history';

The default undo stack: steps in memory, transactions, merging and a depth limit.

const history = new History();

history.execute({ label: 'Rename', do: () => (layer.name = 'B'), undo: () => (layer.name = 'A') });
history.undo();

Implements#

HistoryLike

Constructors#

Constructor#

new History(options?: HistoryOptions): History;

Parameters#

Parameter	Type
`options`	`HistoryOptions`

Returns#

History

Properties#

Property	Modifier	Type	Description	Defined in
`maxDepth`	`public`	`number`	Steps kept. The oldest fall off. Change it at any time.	history.ts:84
`state`	`readonly`	`HistoryState`	`canUndo`, `canRedo` and the labels, as signals for buttons and menus.	history.ts:82

Accessors#

applying#

Get Signature#

get applying(): boolean;

True while undo() or redo() runs. Changes recorded meanwhile are dropped.

Returns

boolean

future#

Get Signature#

get future(): readonly HistoryStep[];

Steps that redo() can apply again, next first.

Returns

readonly HistoryStep[]

grouping#

Get Signature#

get grouping(): boolean;

True while a transaction is open.

Returns

boolean

past#

Get Signature#

get past(): readonly HistoryStep[];

Steps that undo() can revert, oldest first.

Returns

readonly HistoryStep[]

Methods#

begin()#

begin(label?: string): void;

Opens a transaction. Everything recorded until the matching end() becomes one step.

Parameters#

Parameter	Type	Default value
`label`	`string`	`''`

Returns#

void

Implementation of#

HistoryLike.begin

cancel()#

cancel(): void;

Reverts what the open transaction recorded and closes it.

Returns#

void

clear()#

clear(): void;

Forgets every step and drops an open transaction without reverting it.

Returns#

void

end()#

end(): void;

Closes a transaction. The outermost end() pushes the step (an empty one is dropped).

Returns#

void

Implementation of#

HistoryLike.end

execute()#

execute(command: Command): this;

Runs command.do() and records it.

Parameters#

Parameter	Type
`command`	`Command`

Returns#

this

onChange()#

onChange(fn: () => void): () => void;

Calls fn after every change of the stack. Returns the unsubscribe function.

Parameters#

Parameter	Type
`fn`	() => `void`

Returns#

() => void

record()#

record(command: Command): void;

Records a change that is already applied. Clears the redo steps.

Parameters#

Parameter	Type
`command`	`Command`

Returns#

void

Implementation of#

HistoryLike.record

redo()#

redo(): boolean;

Applies the last undone step again, after one end() of an open transaction. Returns false when there is none.

Returns#

boolean

seal()#

seal(): void;

Stops the last step from taking merges: the next change starts a new step.

Returns#

void

transaction()#

transaction<R>(label: string, fn: () => R): R;

Runs fn as one step. If it throws, its changes are reverted and the error rethrown.

Type Parameters#

Type Parameter
`R`

Parameters#

Parameter	Type
`label`	`string`
`fn`	() => `R`

Returns#

R

undo()#

undo(): boolean;

Reverts the last step, after one end() of an open transaction. Returns false when there is none.

Returns#

boolean