Type evented.js

src/util/evented.js

@@ -1,12 +1,16 @@
+// @flow
 
 const util = require('./util');
 
-function _addEventListener(type, listener, listenerList) {
+type Listener = (Object) => any;
+type Listeners = { [string]: Array<Listener> };
+
+function _addEventListener(type: string, listener: Listener, listenerList: Listeners) {
     listenerList[type] = listenerList[type] || [];
     listenerList[type].push(listener);
 }
 
-function _removeEventListener(type, listener, listenerList) {
+function _removeEventListener(type: string, listener: Listener, listenerList: Listeners) {
     if (listenerList && listenerList[type]) {
         const index = listenerList[type].indexOf(listener);
         if (index !== -1) {
@@ -21,6 +25,10 @@ function _removeEventListener(type, listener, listenerList) {
  * @mixin Evented
  */
 class Evented {
+    _listeners: Listeners;
+    _oneTimeListeners: Listeners;
+    _eventedParent: ?Evented;
+    _eventedParentData: ?(Object | () => Object);
 
     /**
      * Adds a listener to a specified event type.
@@ -31,7 +39,7 @@ class Evented {
      *   extended with `target` and `type` properties.
      * @returns {Object} `this`
      */
-    on(type, listener) {
+    on(type: string, listener: Listener) {
         this._listeners = this._listeners || {};
         _addEventListener(type, listener, this._listeners);
 
@@ -45,7 +53,7 @@ class Evented {
      * @param {Function} listener The listener function to remove.
      * @returns {Object} `this`
      */
-    off(type, listener) {
+    off(type: string, listener: Listener) {
         _removeEventListener(type, listener, this._listeners);
         _removeEventListener(type, listener, this._oneTimeListeners);
 
@@ -61,7 +69,7 @@ class Evented {
      * @param {Function} listener The function to be called when the event is fired the first time.
      * @returns {Object} `this`
      */
-    once(type, listener) {
+    once(type: string, listener: Listener) {
         this._oneTimeListeners = this._oneTimeListeners || {};
         _addEventListener(type, listener, this._oneTimeListeners);
 
@@ -75,7 +83,7 @@ class Evented {
      * @param {Object} [data] Data to be passed to any listeners.
      * @returns {Object} `this`
      */
-    fire(type, data) {
+    fire(type: string, data: Object) {
         if (this.listens(type)) {
             data = util.extend({}, data, {type: type, target: this});
 
@@ -112,7 +120,7 @@ class Evented {
      * @param {string} type The event type
      * @returns {boolean} `true` if there is at least one registered listener for specified event type, `false` otherwise
      */
-    listens(type) {
+    listens(type: string) {
         return (
             (this._listeners && this._listeners[type] && this._listeners[type].length > 0) ||
             (this._oneTimeListeners && this._oneTimeListeners[type] && this._oneTimeListeners[type].length > 0) ||
@@ -124,11 +132,9 @@ class Evented {
      * Bubble all events fired by this instance of Evented to this parent instance of Evented.
      *
      * @private
-     * @param {parent}
-     * @param {data}
      * @returns {Object} `this`
      */
-    setEventedParent(parent, data) {
+    setEventedParent(parent: ?Evented, data?: Object | () => Object) {
         this._eventedParent = parent;
         this._eventedParentData = data;