## [event](https://developers.google.com/maps/documentation/javascript/reference/3.63/event.md.txt#event) class `google.maps.event` class Namespace for all public event functions Access by calling `const {event} = await google.maps.importLibrary("core")`. See [Libraries in the Maps JavaScript API](https://developers.google.com/maps/documentation/javascript/libraries.md.txt). | ### Static Methods || |---|---| | `addListener` | `addListener(instance, eventName, handler)` **Parameters:** - `instance`: `Object` - `eventName`: `string` - `handler`: `Function` **Return Value:** `MapsEventListener` Adds the given listener function to the given event name for the given object instance. Returns an identifier for this listener that can be used with removeListener(). | | `addListenerOnce` | `addListenerOnce(instance, eventName, handler)` **Parameters:** - `instance`: `Object` - `eventName`: `string` - `handler`: `Function` **Return Value:** `MapsEventListener` Like addListener, but the handler removes itself after handling the first event. | | `clearInstanceListeners` | `clearInstanceListeners(instance)` **Parameters:** - `instance`: `Object` **Return Value:** `void` Removes all listeners for all events for the given instance. | | `clearListeners` | `clearListeners(instance, eventName)` **Parameters:** - `instance`: `Object` - `eventName`: `string` **Return Value:** `void` Removes all listeners for the given event for the given instance. | | `hasListeners` | `hasListeners(instance, eventName)` **Parameters:** - `instance`: `Object` - `eventName`: `string` **Return Value:** `boolean` Returns if there are listeners for the given event on the given instance. Can be used to save the computation of expensive event details. | | `removeListener` | `removeListener(listener)` **Parameters:** - `listener`: `MapsEventListener` **Return Value:** `void` Removes the given listener, which should have been returned by addListener above. Equivalent to calling `listener.remove()`. | | `trigger` | `trigger(instance, eventName, eventArgs)` **Parameters:** - `instance`: `Object` - `eventName`: `string` - `eventArgs`: `...?` **Return Value:** `void` Triggers the given event. All arguments after eventName are passed as arguments to the listeners. | | `[addDomListener](https://developers.google.com/maps/documentation/javascript/reference/3.63/event#event.addDomListener)` | > [!WARNING] > **[Deprecated:](https://developers.google.com/maps/deprecations.md.txt)** `google.maps.event.addDomListener()` is deprecated, use the standard [addEventListener()](https://developer.mozilla.org/docs/Web/API/EventTarget/addEventListener) method instead. The feature will continue to work and there is no plan to decommission it. `addDomListener(instance, eventName, handler[, capture])` **Parameters:** - `instance`: `Object` - `eventName`: `string` - `handler`: `Function` - `capture`: `boolean optional` **Return Value:** `MapsEventListener` Cross browser event handler registration. This listener is removed by calling removeListener(handle) for the handle that is returned by this function. | | `[addDomListenerOnce](https://developers.google.com/maps/documentation/javascript/reference/3.63/event#event.addDomListenerOnce)` | > [!WARNING] > **[Deprecated:](https://developers.google.com/maps/deprecations.md.txt)** `google.maps.event.addDomListenerOnce()` is deprecated, use the standard [addEventListener()](https://developer.mozilla.org/docs/Web/API/EventTarget/addEventListener) method instead. The feature will continue to work and there is no plan to decommission it. `addDomListenerOnce(instance, eventName, handler[, capture])` **Parameters:** - `instance`: `Object` - `eventName`: `string` - `handler`: `Function` - `capture`: `boolean optional` **Return Value:** `MapsEventListener` Wrapper around addDomListener that removes the listener after the first event. | ## [MapsEventListener](https://developers.google.com/maps/documentation/javascript/reference/3.63/event.md.txt#MapsEventListener) interface `google.maps.MapsEventListener` interface An event listener, created by `google.maps.event.addListener()` and friends. | ### Methods || |---|---| | `remove` | `remove()` **Parameters:** None **Return Value:** `void` Removes the listener. Calling `listener.remove()` is equivalent to `google.maps.event.removeListener(listener)`. | ## [MVCObject](https://developers.google.com/maps/documentation/javascript/reference/3.63/event.md.txt#MVCObject) class `google.maps.MVCObject` class Base class implementing KVO. The `MVCObject` constructor is guaranteed to be an empty function, and so you may inherit from `MVCObject` by writing `MySubclass.prototype = new google.maps.MVCObject();`. Unless otherwise noted, this is not true of other classes in the API, and inheriting from other classes in the API is not supported. Access by calling `const {MVCObject} = await google.maps.importLibrary("core")`. See [Libraries in the Maps JavaScript API](https://developers.google.com/maps/documentation/javascript/libraries.md.txt). | ### Constructor || |---|---| | `MVCObject` | `MVCObject()` **Parameters:** None Creates an `MVCObject`. | | ### Methods || |---|---| | `addListener` | `addListener(eventName, handler)` **Parameters:** - `eventName`: `string` - `handler`: `Function` **Return Value:** `MapsEventListener` Adds the given listener function to the given event name. Returns an identifier for this listener that can be used with `google.maps.event.removeListener`. | | `bindTo` | `bindTo(key, target[, targetKey, noNotify])` **Parameters:** - `key`: `string` - `target`: `MVCObject` - `targetKey`: `string optional` - `noNotify`: `boolean optional` **Return Value:** None Binds a View to a Model. | | `get` | `get(key)` **Parameters:** - `key`: `string` **Return Value:** `?` Gets a value. | | `notify` | `notify(key)` **Parameters:** - `key`: `string` **Return Value:** None Notify all observers of a change on this property. This notifies both objects that are bound to the object's property as well as the object that it is bound to. | | `set` | `set(key, value)` **Parameters:** - `key`: `string` - `value`: `*` **Return Value:** None Sets a value. | | `setValues` | `setValues([values])` **Parameters:** - `values`: `Object optional` **Return Value:** None Sets a collection of key-value pairs. | | `unbind` | `unbind(key)` **Parameters:** - `key`: `string` **Return Value:** None Removes a binding. Unbinding will set the unbound property to the current value. The object will not be notified, as the value has not changed. | | `unbindAll` | `unbindAll()` **Parameters:** None **Return Value:** None Removes all bindings. | ## [MVCArray](https://developers.google.com/maps/documentation/javascript/reference/3.63/event.md.txt#MVCArray) class `google.maps.MVCArray` class This class extends `MVCObject`. Access by calling `const {MVCArray} = await google.maps.importLibrary("core")`. See [Libraries in the Maps JavaScript API](https://developers.google.com/maps/documentation/javascript/libraries.md.txt). | ### Constructor || |---|---| | `MVCArray` | `MVCArray([array])` **Parameters:** - `array`: `Array optional` A mutable MVC Array. | | ### Methods || |---|---| | `clear` | `clear()` **Parameters:** None **Return Value:** None Removes all elements from the array. | | `forEach` | `forEach(callback)` **Parameters:** - `callback`: `function(T, number): void` **Return Value:** None Iterate over each element, calling the provided callback. The callback is called for each element like: callback(element, index). | | `getArray` | `getArray()` **Parameters:** None **Return Value:** `Array` Returns a reference to the underlying Array. Warning: if the Array is mutated, no events will be fired by this object. | | `getAt` | `getAt(i)` **Parameters:** - `i`: `number` **Return Value:** `T` Returns the element at the specified index. | | `getLength` | `getLength()` **Parameters:** None **Return Value:** `number` Returns the number of elements in this array. | | `insertAt` | `insertAt(i, elem)` **Parameters:** - `i`: `number` - `elem`: `T` **Return Value:** None Inserts an element at the specified index. | | `pop` | `pop()` **Parameters:** None **Return Value:** `T` Removes the last element of the array and returns that element. | | `push` | `push(elem)` **Parameters:** - `elem`: `T` **Return Value:** `number` Adds one element to the end of the array and returns the new length of the array. | | `removeAt` | `removeAt(i)` **Parameters:** - `i`: `number` **Return Value:** `T` Removes an element from the specified index. | | `setAt` | `setAt(i, elem)` **Parameters:** - `i`: `number` - `elem`: `T` **Return Value:** None Sets an element at the specified index. | | ### Events || |---|---| | `insert_at` | `function(index)` **Arguments:** - `index`: `number` This event is fired when `insertAt()` is called. The event passes the index that was passed to `insertAt()`. | | `remove_at` | `function(index, removed)` **Arguments:** - `index`: `number` - `removed`: `T` The element removed from the array at `index`. This event is fired when `removeAt()` is called. The event passes the index that was passed to `removeAt()` and the element that was removed from the array. | | `set_at` | `function(index, previous)` **Arguments:** - `index`: `number` - `previous`: `T` The element that was previously in the array at `index`. This event is fired when `setAt()` is called. The event passes the index that was passed to `setAt()` and the element that was previously in the array at that index. | ## [ErrorEvent](https://developers.google.com/maps/documentation/javascript/reference/3.63/event.md.txt#ErrorEvent) interface `google.maps.ErrorEvent` interface An event with an associated Error. | ### Properties || |---|---| | `error` | **Type:** `Error` The Error related to the event. |