https://github.com/maksims/mr-eventemitter
Provides the ability to subscribe and emit events in sync manner. With a focus on performance and memory efficiency.
https://github.com/maksims/mr-eventemitter
emit-events eventemitter
Last synced: 2 months ago
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Provides the ability to subscribe and emit events in sync manner. With a focus on performance and memory efficiency.
- Host: GitHub
- URL: https://github.com/maksims/mr-eventemitter
- Owner: Maksims
- License: mit
- Created: 2020-12-25T22:18:28.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2021-07-06T11:29:27.000Z (about 4 years ago)
- Last Synced: 2024-11-19T02:47:12.889Z (11 months ago)
- Topics: emit-events, eventemitter
- Language: JavaScript
- Homepage:
- Size: 149 KB
- Stars: 16
- Watchers: 4
- Forks: 3
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# mr-EventEmitter
Provides ability to subscribe and emit events. This event emitter is tailored for real-time applications so is designed with performance and memory efficiency in mind.
Also it has two build targets: ES5 (ECMA2009) and ES8+ (modern JS), to maximize [browser support](#Browser) without sacrificing benefits of modern JS for majority of users.
[](LICENSE)
## :rocket: Install
#### Node.js
Install:
```bash
npm install mr-eventemitter
```
In code:
```js
const EventEmitter = require('mr-eventemitter');
```
#### Browser
```html
```
Use built files from a `dist` directory for the browser. It will load ES8+ version if it is supported ([~94%](https://caniuse.com/?search=ES8)), otherwise it will load ES5 (ECMA2009) version that supports pretty much [every](https://caniuse.com/?search=ES5) platform.
#### CDN ([jsDelivr](https://www.jsdelivr.com/))
You can use a public CDN for the library:
ES8+ module: https://cdn.jsdelivr.net/npm/mr-eventemitter@0.1/dist/mr-eventemitter.min.js
ES5 version: https://cdn.jsdelivr.net/npm/mr-eventemitter@0.1/dist/mr-eventemitter.es5.min.js
#### Example
```js
let obj = new EventEmitter();
obj.on('event', (a) => {
console.log('event', a);
});
obj.emit('event', 42);
```
## :scroll: [API Documentation](API.md)
## Usage
#### Creating:
Creating event emitter directly:
```js
let obj = new EventEmitter();
```
With class:
```js
class World extends EventEmitter {
contrunctor() {
super();
}
}
```
With prototype:
```js
function World() {
EventEmitter.call(this);
}
World.prototype = Object.create(EventEmitter.prototype);
World.prototype.constructor = World;
```
#### Emitting:
```js
obj.emit('event', 42);
```
Or with many arguments:
```js
obj.emit('event', 4, 8, 16, 32);
```
#### Subscribing:
```js
obj.on('event', function(value) {
console.log('event', value);
});
```
It is possible to pass to an event many arguments:
```js
obj.on('event', function(a, b, c, d) {
console.log('event', a, b, c, d);
});
```
For single life event use `once`:
```js
obj.once('event', function(value) {
console.log('event', value);
});
```
Sometimes providing scope for a callback function is usefull:
```js
class Place {
constructor() {
this.name = 'Home';
world.on('event', function() {
// this - will be this `Place` instead of `world`
console.log('event', this.name); // hello Home
}, this); // - notice `this`
}
}
```
#### Removing events:
To remove event handler, you can use `off` method on EventEmitter:
```js
obj.off('event', fn);
```
To remove all events by name:
```js
obj.off('event');
```
Remove a group of events, that match a regular expression:
```js
obj.off(/input:\w+/);
obj.emit('init');
obj.emit('input:start'); // ignored
obj.emit('input:end'); // ignored
```
To remove all events:
```js
obj.off();
```
And for easier management, `on` and `once` methods return **EventHandler**, which then can be used for removing events:
```js
let evt = obj.on('event', (value) => {
console.log('event', value);
});
evt.off();
```
## Building
Builds a single file into two ES5 and ES8+ versions using Babel and Terser.
Source file: `src/index.js`
Built versions ES5 (`dist/mr-eventemitter.es5.min.js`) and ES8+ (`dist/mr-eventemitter.min.js`):
```bash
npm install
npm run build
```