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Class: AnnotationHistoryManager

Core. AnnotationHistoryManager

The manager of the Annotation history state for undoing and redoing annotation changes

new AnnotationHistoryManager()

Extends

Methods

addEventListener(type, fn [, options])

Add a handler to the given event name
Parameters:
Name Type Argument Description
type string | number The name of the event to listen to
fn function The handler to be called when the event is triggered
options object <optional>
 Optional options object for addEventListener
Properties
Name Type Description
once boolean If true then the handler will be called only once
Inherited From:
Returns:
Returns the object that 'addEventListener' is being called on
Type
object
Example
myObject.addEventListener('eventName', (eventParameter1, eventParameter2) => {
  ...
});

canRedo()

Returns whether there is a change available to redo
Returns:
Whether there is a change that can be redone or not
Type
boolean

canUndo()

Returns whether there is a change available to undo
Returns:
Whether there is a change that can be undone or not
Type
boolean

clear()

Clears the undo/redo history so that no older changes can be undone.

off( [type] [, fn])

Remove a handler of the given event name
Parameters:
Name Type Argument Description
type string | number <optional>
 The name of the event to remove the handler of. If type is undefined, all the handlers of the object will be removed
fn function <optional>
 The handler associated with this event to be removed. If fn is undefined, all the handlers of the given event name will be removed
Inherited From:
Deprecated:
Returns:
Returns the object that 'off' is being called on
Type
object
Example
myObject.off();
myObject.off('eventName');
myObject.off('eventName', fn);

on(type, fn)

Add a handler to the given event name
Parameters:
Name Type Description
type string | number The name of the event to listen to
fn function The handler to be called when the event is triggered
Inherited From:
Deprecated:
Returns:
Returns the object that 'on' is being called on
Type
object
Example
myObject.on('eventName', (eventParameter1, eventParameter2) => {
  ...
});

one(type, fn)

Same as 'on' except the handler will be called only once
Parameters:
Name Type Description
type string | number The name of the event to listen to
fn function The handler to be called when the event is triggered
Inherited From:
Deprecated:
  • Since version 8.0. Use addEventListener with {'once': true} as options instead.
Returns:
Returns the object that 'one' is being called on
Type
object
Example
myObject.one('eventName', (eventParameter1, eventParameter2) => {
 ...
});

redo()

Reapplies the most recent annotation change that was undone
Returns:
Returns a promise that resolves when the operation is complete
Type
Promise.<void>

removeEventListener( [type] [, fn])

Remove a handler of the given event name
Parameters:
Name Type Argument Description
type string | number <optional>
 The name of the event to remove the handler of. If type is undefined, all the handlers of the object will be removed
fn function <optional>
 The handler associated with this event to be removed. If fn is undefined, all the handlers of the given event name will be removed
Inherited From:
Deprecated:
  • for version 9.0. Use [removeEventListener] with fn specified
Returns:
Returns the object that 'removeEventListener' is being called on
Type
object
Example
myObject.removeEventListener();
myObject.removeEventListener('eventName');
myObject.removeEventListener('eventName', fn);

trigger(type [, data])

Calls the handlers of the event name with given data
Parameters:
Name Type Argument Description
type string | number event name of which the handlers will be called.
data * <optional>
 data that will be passed to the handlers. If data is an array, it will be spread and then passed to the handlers
Inherited From:
Returns:
Returns the object that 'trigger' is being called on
Type
object
Example
myObject.trigger('eventName');
myObject.trigger('eventName', [eventParameter1, eventParameter2]);

undo()

Undoes the most recent annotation change
Returns:
Returns a promise that resolves when the operation is complete
Type
Promise.<void>

Events

historyChanged

Triggered when the annotation history stack changes. This could be used to check the canUndo or canRedo functions if their value has changed.