https://github.com/gamtiq/neva
Simple library to work with custom events
https://github.com/gamtiq/neva
dispatch emitter event event-handler eventbus eventemitter listener pub-sub subscription
Last synced: about 1 year ago
JSON representation
Simple library to work with custom events
- Host: GitHub
- URL: https://github.com/gamtiq/neva
- Owner: gamtiq
- License: mit
- Created: 2017-04-15T18:51:31.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2021-02-23T17:48:35.000Z (about 5 years ago)
- Last Synced: 2024-12-21T09:33:39.592Z (about 1 year ago)
- Topics: dispatch, emitter, event, event-handler, eventbus, eventemitter, listener, pub-sub, subscription
- Language: JavaScript
- Homepage: https://gamtiq.github.io/neva/
- Size: 830 KB
- Stars: 0
- Watchers: 3
- Forks: 1
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- Changelog: History.md
- License: LICENSE-MIT
Awesome Lists containing this project
README
Simple library to work with custom events.
[](http://badge.fury.io/js/neva)
[](http://travis-ci.org/gamtiq/neva)
[](http://gruntjs.com/)
* Simple event emitter API: `on`, `off`, `emit`, `hasEventHandler`.
* Event emitter API is chainable.
* Events can be emitted with multiple attached parameters.
* Data about emitted event are wrapped into an object with uniform structure that is passed to handlers.
* Ability to add event handler that should be called just once.
* Ability to enhance prototype of constructor function (class) with event emitter API (emitter methods can be mixed in `prototype`).
* Available as ECMAScript 6/2015 module, CommonJS module or UMD.
* Work in any ECMAScript 3+ environment (browsers, Node.js etc).
* Small.
## Table of contents
* [Installation](#install)
* [Usage](#usage)
* [Examples](#examples)
* [API](#api)
* [Contributing](#contributing)
* [License](#license)
### Node
npm install neva
### [Bower](https://bower.io)
bower install neva
### AMD, <script>
Use `dist/neva.js` or `dist/neva.min.js` (minified version).
### ECMAScript 6+
```js
import getEmitter from 'neva';
```
### Node
```js
const getEmitter = require('neva').getEmitter;
```
### AMD
```js
define(['path/to/dist/neva.js'], function(neva) {
const getEmitter = neva.getEmitter;
});
```
### Bower, <script>
```html
// neva is available via neva field of window object
const getEmitter = neva.getEmitter;
```
```js
const emitter = getEmitter();
const eventHandler = (event) => {
console.log('eventHandler: event type -', event.type, ', data -', event.data);
};
const obj = {
name: 'obj',
handler(event) {
console.log(`${this.name}.handler: event type -`, event.type, ', params -', event.params);
}
};
function onceHandler(event) {
console.log('onceHandler: event type -', event.type, ', data -', event.data);
}
emitter.on(['event1', 'event2'], eventHandler)
.on('event1', obj.handler, obj)
.on('event2', onceHandler, null, {once: true});
emitter.emit('event1', 1, 2, 3)
.emit({type: 'event2', data: 'some data', qty: 8});
// The following will be printed into console:
// eventHandler: event type - event1 , data - 1
// obj.handler: event type - event1 , params - Array [ 1, 2, 3 ]
// eventHandler: event type - event2 , data - some data
// onceHandler: event type - event2 , data - some data
emitter.hasEventHandler('event1', eventHandler); // true
emitter.hasEventHandler('event2', onceHandler); // false
emitter.off('event1', eventHandler);
emitter.hasEventHandler('event1', eventHandler); // false
emitter.hasEventHandler('event1'); // true
emitter.off('event1');
emitter.hasEventHandler('event1'); // false
emitter.hasEventHandler(); // true
emitter.off();
emitter.hasEventHandler(); // false
class SomeClass {
...
}
// Add event emitter methods to class
getEmitter(SomeClass.prototype);
```
### getEmitter([target: Object]): EventEmitter
Create event emitter or add methods to work with events into specified object.
`target` can be prototype of some constructor function (class).
### EventEmitter API
#### on(type: string | string[], handler: Function, [context: Object], [settings: HandlerSettings]): EventEmitter
Register a handler for the specified event type(s).
#### off(type: string, handler: Function, [context: Object]): EventEmitter
Remove the specified event handler.
#### off(type: string): EventEmitter
Remove all handlers for the given event type.
#### off(): EventEmitter
Remove all registered event handlers.
#### emit(type: string, [param1: any, param2: any, ...]): EventEmitter
Call all handlers for the specified event type.
An object with the following fields will be passed in each handler:
* `type: string` - the event type (value of `type` parameter).
* `params: Array` - list of additional parameters that are passed besides the event type (`[param1, param2, ...]`).
* `data: any` - value of the second function's parameter (value of `params[0]`).
#### emit({type: string, ...}): EventEmitter
Call all handlers for the specified event type and pass the given object in each handler.
#### hasEventHandler(type: string, handler: Function, [context: Object]): boolean
Check whether the specified event handler is registered.
#### hasEventHandler(type: string): boolean
Check whether any handler for the specified event type is registered.
#### hasEventHandler(): boolean
Check whether any event handler is registered.
See [`docs`](https://gamtiq.github.io/neva/) for details.
## Contributing [↑](#start)
In lieu of a formal styleguide, take care to maintain the existing coding style.
Add unit tests for any new or changed functionality.
Lint and test your code using [Grunt](http://gruntjs.com/).
## License [↑](#start)
Copyright (c) 2017-2021 Denis Sikuler
Licensed under the MIT license.