OpenLayers

Class: BaseObject

ol/Object~BaseObject 


import BaseObject from 'ol/Object';

Abstract base class; normally only used for creating subclasses and not instantiated in apps. Most non-trivial classes inherit from this.

This extends module:ol/Observable with observable properties, where each property is observable as well as the object as a whole.

Classes that inherit from this have pre-defined properties, to which you can add your owns. The pre-defined properties are listed in this documentation as 'Observable Properties', and have their own accessors; for example, module:ol/Map~Map has a target property, accessed with getTarget() and changed with setTarget(). Not all properties are however settable. There are also general-purpose accessors get() and set(). For example, get('target') is equivalent to getTarget().

The set accessors trigger a change event, and you can monitor this by registering a listener. For example, module:ol/View~View has a center property, so view.on('change:center', function(evt) {...}); would call the function whenever the value of the center property changes. Within the function, evt.target would be the view, so evt.target.getCenter() would return the new center.

You can add your own observable properties with object.set('prop', 'value'), and retrieve that with object.get('prop'). You can listen for changes on that property value with object.on('change:prop', listener). You can get a list of all properties with module:ol/Object~BaseObject#getProperties.

Note that the observable properties are separate from standard JS properties. You can, for example, give your map object a title with map.title='New title' and with map.set('title', 'Another title'). The first will be a hasOwnProperty; the second will appear in getProperties(). Only the second is observable.

Properties can be deleted by using the unset method. E.g. object.unset('foo').

new BaseObject(opt_values)

Object.js, line 88
Name Type Description
values Object.<string, *>

An object with key-value pairs.
Fires:

Subclasses

Extends

Methods

changed() inherited

Observable.js, line 36

Increases the revision counter and dispatches a 'change' event.

get(key){*}

Object.js, line 119

Gets a value.

Name Type Description
key string

Key name.
Returns:
Value.

getKeys(){Array.<string>}

Object.js, line 132

Get a list of object property names.

Returns:
List of property names.

getProperties(){Object.<string, *>}

Object.js, line 141

Get an object of all property names and values.

Returns:
Object.

getRevision(){number} inherited

Observable.js, line 47

Get the version number for this object. Each time the object is modified, its version number will be incremented.

Returns:
Revision.

on(type, listener){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited

Observable.js, line 60

Listen for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.
listener function

The listener function.
Returns:
Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

once(type, listener){module:ol/events~EventsKey|Array.<module:ol/events~EventsKey>} inherited

Observable.js, line 82

Listen once for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.
listener function

The listener function.
Returns:
Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

set(key, value, opt_silent)

Object.js, line 164

Sets a value.

Name Type Description
key string

Key name.
value *

Value.
silent boolean

Update without triggering an event.

setProperties(values, opt_silent)

Object.js, line 183

Sets a collection of key-value pairs. Note that this changes any existing properties and adds new ones (it does not remove any existing properties).

Name Type Description
values Object.<string, *>

Values.
silent boolean

Update without triggering an event.

un(type, listener) inherited

Observable.js, line 101

Unlisten for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.
listener function

The listener function.

unset(key, opt_silent)

Object.js, line 195

Unsets a property.

Name Type Description
key string

Key name.
silent boolean

Unset without triggering an event.