events.js
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function callbacksFor(object) {
let callbacks = object._promiseCallbacks;
if (!callbacks) {
callbacks = object._promiseCallbacks = {};
}
return callbacks;
}
/**
@class EventTarget
@for rsvp
@public
*/
export default {
/**
`EventTarget.mixin` extends an object with EventTarget methods. For
Example:
```javascript
import EventTarget from 'rsvp';
let object = {};
EventTarget.mixin(object);
object.on('finished', function(event) {
// handle event
});
object.trigger('finished', { detail: value });
```
`EventTarget.mixin` also works with prototypes:
```javascript
import EventTarget from 'rsvp';
let Person = function() {};
EventTarget.mixin(Person.prototype);
let yehuda = new Person();
let tom = new Person();
yehuda.on('poke', function(event) {
console.log('Yehuda says OW');
});
tom.on('poke', function(event) {
console.log('Tom says OW');
});
yehuda.trigger('poke');
tom.trigger('poke');
```
@method mixin
@for rsvp
@private
@param {Object} object object to extend with EventTarget methods
*/
mixin(object) {
object.on = this.on;
object.off = this.off;
object.trigger = this.trigger;
object._promiseCallbacks = undefined;
return object;
},
/**
Registers a callback to be executed when `eventName` is triggered
```javascript
object.on('event', function(eventInfo){
// handle the event
});
object.trigger('event');
```
@method on
@for EventTarget
@private
@param {String} eventName name of the event to listen for
@param {Function} callback function to be called when the event is triggered.
*/
on(eventName, callback) {
if (typeof callback !== 'function') {
throw new TypeError('Callback must be a function');
}
let allCallbacks = callbacksFor(this);
let callbacks = allCallbacks[eventName];
if (!callbacks) {
callbacks = allCallbacks[eventName] = [];
}
if (callbacks.indexOf(callback) === -1) {
callbacks.push(callback);
}
},
/**
You can use `off` to stop firing a particular callback for an event:
```javascript
function doStuff() { // do stuff! }
object.on('stuff', doStuff);
object.trigger('stuff'); // doStuff will be called
// Unregister ONLY the doStuff callback
object.off('stuff', doStuff);
object.trigger('stuff'); // doStuff will NOT be called
```
If you don't pass a `callback` argument to `off`, ALL callbacks for the
event will not be executed when the event fires. For example:
```javascript
let callback1 = function(){};
let callback2 = function(){};
object.on('stuff', callback1);
object.on('stuff', callback2);
object.trigger('stuff'); // callback1 and callback2 will be executed.
object.off('stuff');
object.trigger('stuff'); // callback1 and callback2 will not be executed!
```
@method off
@for rsvp
@private
@param {String} eventName event to stop listening to
@param {Function} callback optional argument. If given, only the function
given will be removed from the event's callback queue. If no `callback`
argument is given, all callbacks will be removed from the event's callback
queue.
*/
off(eventName, callback) {
let allCallbacks = callbacksFor(this);
if (!callback) {
allCallbacks[eventName] = [];
return;
}
let callbacks = allCallbacks[eventName];
let index = callbacks.indexOf(callback);
if (index !== -1) {
callbacks.splice(index, 1);
}
},
/**
Use `trigger` to fire custom events. For example:
```javascript
object.on('foo', function(){
console.log('foo event happened!');
});
object.trigger('foo');
// 'foo event happened!' logged to the console
```
You can also pass a value as a second argument to `trigger` that will be
passed as an argument to all event listeners for the event:
```javascript
object.on('foo', function(value){
console.log(value.name);
});
object.trigger('foo', { name: 'bar' });
// 'bar' logged to the console
```
@method trigger
@for rsvp
@private
@param {String} eventName name of the event to be triggered
@param {*} options optional value to be passed to any event handlers for
the given `eventName`
*/
trigger(eventName, options, label) {
let allCallbacks = callbacksFor(this);
let callbacks = allCallbacks[eventName];
if (callbacks) {
// Don't cache the callbacks.length since it may grow
let callback;
for (let i = 0; i < callbacks.length; i++) {
callback = callbacks[i];
callback(options, label);
}
}
}
};