# Class: Link

This documentation is for OpenLayers v10.9.0. The latest is v.

## ol/interaction/Link~Link

    import Link from 'ol/interaction/Link.js';

An interaction that synchronizes the map state with the URL.

#### new Link(options)

interaction/Link.js, line 79

  Name | Type | Description
  --- | --- | ---
  `animate` | boolean | AnimationOptions (defaults to true) | Animate view transitions.
  `params` | Array<Params> (defaults to ['x', 'y', 'z', 'r', 'l']) | Properties to track. Default is to track `x` (center x), `y` (center y), `z` (zoom), `r` (rotation) and `l` (layers).
  `replace` | boolean (defaults to false) | Replace the current URL without creating the new entry in browser history. By default, changes in the map state result in a new entry being added to the browser history.
  `prefix` | string (defaults to '') | By default, the URL will be updated with search parameters x, y, z, and r. To avoid collisions with existing search parameters that your application uses, you can supply a custom prefix for the ones used by this interaction (e.g. 'ol:').

  ##### Fires:

  - `change` (BaseEvent) - Generic change event. Triggered when the revision counter is increased.
  - `change:active` (ObjectEvent)
  - `error` (BaseEvent) - Generic error event. Triggered when an error occurs.
  - `propertychange` (ObjectEvent) - Triggered when a property is changed.

### Extends

- Interaction

### Observable Properties

Name | Type | Settable | ObjectEvent type | Description
--- | --- | --- | --- | ---
`active` | boolean | yes | `change:active` | `true` if the interaction is active, `false` otherwise.

### Methods

#### changed() inherited

Observable.js, line 68

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

#### dispatchEvent(event){boolean | undefined} inherited

events/Target.js, line 85

  Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a `type` property.

  Name | Type | Description
  --- | --- | ---
  `event` | BaseEvent | string | Event object.

  ##### Returns:

  `false` if anyone called preventDefault on the event object or if any of the listeners returned false.

#### get(key){*} inherited

Object.js, line 136

  Gets a value.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.

  ##### Returns:

  Value.

#### getActive(){boolean} inherited

interaction/Interaction.js, line 82

  Return whether the interaction is currently active.

  ##### Returns:

  `true` if the interaction is active, `false` otherwise.

#### getKeys(){Array.<string>} inherited

Object.js, line 149

  Get a list of object property names.

  ##### Returns:

  List of property names.

#### getMap(){Map | null} inherited

interaction/Interaction.js, line 91

  Get the map associated with this interaction.

  ##### Returns:

  Map.

#### getProperties(){NoInfer.<Properties>} inherited

Object.js, line 158

  Get an object of all property names and values.

  ##### Returns:

  Object.

#### getRevision(){number} inherited

Observable.js, line 79

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

  ##### Returns:

  Revision.

#### handleEvent(mapBrowserEvent){boolean} inherited

interaction/Interaction.js, line 101

  Handles the `map browser event`.

  Name | Type | Description
  --- | --- | ---
  `mapBrowserEvent` | MapBrowserEvent | Map browser event.

  ##### Returns:

  `false` to stop event propagation.

#### on(type, listener){EventsKey | Array<EventsKey>} inherited

Observable.js, line 152

  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){EventsKey | Array<EventsKey>} inherited

Observable.js, line 164

  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, silent) inherited

Object.js, line 218

  Sets a value.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.
  `value` | * | Value.
  `silent` | boolean | undefined | Update without triggering an event.

#### setActive(active) inherited

interaction/Interaction.js, line 111

  Activate or deactivate the interaction.

  Name | Type | Description
  --- | --- | ---
  `active` | boolean | Active.

#### setProperties(values, silent) inherited

Object.js, line 238

  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` | Partial.<NoInfer.<Properties>> | Values.
  `silent` | boolean | undefined | Update without triggering an event.

#### track(key, callback){string | null}

interaction/Link.js, line 384

  Register a listener for a URL search parameter. The callback will be called with a new value when the corresponding search parameter changes due to history events (e.g. browser navigation).

  Name | Type | Description
  --- | --- | ---
  `key` | string | The URL search parameter.
  `callback` | Callback | The function to call when the search parameter changes.

  ##### Returns:

  The initial value of the search parameter (or null if absent from the URL).

#### un(type, listener) inherited

Observable.js, line 173

  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, silent) inherited

Object.js, line 262

  Unsets a property.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.
  `silent` | boolean | undefined | Unset without triggering an event.

#### update(key, value)

interaction/Link.js, line 401

  Update the URL with a new search parameter value. If the value is null, it will be deleted from the search parameters.

  Name | Type | Description
  --- | --- | ---
  `key` | string | The URL search parameter.
  `value` | string | null | The updated value (or null to remove it from the URL).