Readme.md (1446B)
1 # Emitter [](https://travis-ci.org/component/emitter) 2 3 Event emitter component. 4 5 ## Installation 6 7 ``` 8 $ component install component/emitter 9 ``` 10 11 ## API 12 13 ### Emitter(obj) 14 15 The `Emitter` may also be used as a mixin. For example 16 a "plain" object may become an emitter, or you may 17 extend an existing prototype. 18 19 As an `Emitter` instance: 20 21 ```js 22 var Emitter = require('emitter'); 23 var emitter = new Emitter; 24 emitter.emit('something'); 25 ``` 26 27 As a mixin: 28 29 ```js 30 var Emitter = require('emitter'); 31 var user = { name: 'tobi' }; 32 Emitter(user); 33 34 user.emit('im a user'); 35 ``` 36 37 As a prototype mixin: 38 39 ```js 40 var Emitter = require('emitter'); 41 Emitter(User.prototype); 42 ``` 43 44 ### Emitter#on(event, fn) 45 46 Register an `event` handler `fn`. 47 48 ### Emitter#once(event, fn) 49 50 Register a single-shot `event` handler `fn`, 51 removed immediately after it is invoked the 52 first time. 53 54 ### Emitter#off(event, fn) 55 56 * Pass `event` and `fn` to remove a listener. 57 * Pass `event` to remove all listeners on that event. 58 * Pass nothing to remove all listeners on all events. 59 60 ### Emitter#emit(event, ...) 61 62 Emit an `event` with variable option args. 63 64 ### Emitter#listeners(event) 65 66 Return an array of callbacks, or an empty array. 67 68 ### Emitter#hasListeners(event) 69 70 Check if this emitter has `event` handlers. 71 72 ## License 73 74 MIT