OpenLayers 3

Class: Collection

ol.Collection

An expanded version of standard JS Array, adding convenience methods for manipulation. Add and remove changes to the Collection trigger a Collection event. Note that this does not cover changes to the objects within the Collection; they trigger events on the appropriate object, not on the Collection as a whole.

new ol.Collection(opt_array)

src/ol/collection.js, line 86
Name Type Description
array Array.<T>

Array.
Fires:

Extends

Observable Properties

Name Type Settable ol.ObjectEvent type Description
length number no change:length

The length of the array.

Methods

changed() inherited experimental

src/ol/observable.js, line 52

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

Fires:
  • change experimental

clear()

src/ol/collection.js, line 106

Remove all elements from the collection.

extend(arr){ol.Collection.<T>}

src/ol/collection.js, line 120

Add elements to the collection. This pushes each item in the provided array to the end of the collection.

Name Type Description
arr Array.<T>

Array.
Returns:
This collection.

forEach(f, opt_this)

src/ol/collection.js, line 138

Iterate over each element, calling the provided callback.

Name Type Description
f function

The function to call for every element. This function takes 3 arguments (the element, the index and the array). The return value is ignored.
this S

The object to use as this in f.

get(key){*} inherited

src/ol/object.js, line 150

Gets a value.

Name Type Description
key string

Key name.
Returns:
Value.

getArray(){Array.<T>}

src/ol/collection.js, line 151

Get a reference to the underlying Array object. Warning: if the array is mutated, no events will be dispatched by the collection, and the collection's "length" property won't be in sync with the actual length of the array.

Returns:
Array.

getKeys(){Array.<string>} inherited

src/ol/object.js, line 164

Get a list of object property names.

Returns:
List of property names.

getLength(){number}

src/ol/collection.js, line 173

Get the length of this collection.

Returns:
The length of the array.

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

src/ol/object.js, line 174

Get an object of all property names and values.

Returns:
Object.

getRevision(){number} inherited experimental

src/ol/observable.js, line 62
Returns:
Revision.

insertAt(index, elem)

src/ol/collection.js, line 184

Insert an element at the provided index.

Name Type Description
index number

Index.
elem T

Element.

item(index){T}

src/ol/collection.js, line 162

Get the element at the provided index.

Name Type Description
index number

Index.
Returns:
Element.

on(type, listener, opt_this){goog.events.Key} inherited

src/ol/observable.js, line 75

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.
this Object

The object to use as this in listener.
Returns:
Unique key for the listener.

once(type, listener, opt_this){goog.events.Key} inherited

src/ol/observable.js, line 88

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.
this Object

The object to use as this in listener.
Returns:
Unique key for the listener.

pop(){T|undefined}

src/ol/collection.js, line 198

Remove the last element of the collection and return it. Return undefined if the collection is empty.

Returns:
Element.

push(elem){number}

src/ol/collection.js, line 209

Insert the provided element at the end of the collection.

Name Type Description
elem T

Element.
Returns:
Length.

remove(elem){T|undefined}

src/ol/collection.js, line 222

Remove the first occurrence of an element from the collection.

Name Type Description
elem T

Element.
Returns:
The removed element or undefined if none found.

removeAt(index){T|undefined}

src/ol/collection.js, line 241

Remove the element at the provided index and return it. Return undefined if the collection does not contain this index.

Name Type Description
index number

Index.
Returns:
Value.

set(key, value) inherited

src/ol/object.js, line 203

Sets a value.

Name Type Description
key string

Key name.
value *

Value.

setAt(index, elem)

src/ol/collection.js, line 257

Set the element at the provided index.

Name Type Description
index number

Index.
elem T

Element.

setProperties(values) inherited

src/ol/object.js, line 216

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.

un(type, listener, opt_this) inherited

src/ol/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.
this Object

The object which was used as this by the listener.

unByKey(key) inherited

src/ol/observable.js, line 114

Removes an event listener using the key returned by on() or once(). Note that using the ol.Observable.unByKey static function is to be preferred.

Name Type Description
key goog.events.Key

The key returned by on() or once().

unset(key) inherited

src/ol/object.js, line 229

Unsets a property.

Name Type Description
key string

Key name.