# js-event-bus
Simple Event Bus library built for any JavaScript application.
## Installation
### Using npm
```
npm i js-event-bus --save
```
### Using yarn
```
yarn add js-event-bus
```
## Usage
This library was built so you can use it in any JS application like Node.js apps, browser apps etc. The API is always the same.
### Importing in Node.js application
If you want to use it in your Node.js apps you can import the library like this:
```js
const eventBus = require('js-event-bus')();
```
### Importing in browser application
If you want to use it in your Browser apps you can import the library like this:
```html
Put your content here
```
### Api of the library
#### Register to an event
```js
eventBus.on('my-event', function () {
console.log('Inside `my-event`');
});
```
With this code, each time `my-event` is emited this function will be executed.
#### Register only one time to an event
```js
eventBus.once('my-event', function () {
console.log('Inside `my-event`. It\'ll be executed only one time!');
});
```
With this code, when `my-event` is emited this function will be executed. The next triggers of this event won't execute the callback because it is a one time event.
#### Register several time to an event
```js
eventBus.exactly(3, 'my-event', function () {
console.log('Inside `my-event`. It\'ll be executed only 3 times!');
});
```
With this code, when `my-event` is emited this function will be executed with a maximum of triggers of 3.
#### Register using wildcards
You can use wildcards to register listeners using a specific pattern.
```js
eventBus.on('my-event.*', function () {
console.log('Inside `my-event.*`');
});
```
The callback will be executed with the events like `my-event.x`.
* `my-event.x` **will** trigger the callback ;
* `my-event.y` **will** trigger the callback ;
* `my-event` **will not** trigger the callback ;
* `my-event.x.y` **will not** trigger the callback ;
You can also use multiple wildcards to register listeners using a specific pattern.
```js
eventBus.on('my-event.*.name.**', function () {
console.log('my-event.*.name.**`');
});
```
The callback will be executed with the events like `my-event.a.name.b.c`.
* `my-event.a.name.b.c` **will** trigger the callback ;
* `my-event.a.name.b` **will** trigger the callback ;
* `my-event.name.b` **will not** trigger the callback ;
#### Emit an event
You can emit an event by calling the `emit` function. The arguments are the following:
- the name of the event ;
- the context with which it will be fired ;
- ... all the arguments.
Here are some examples:
```js
eventBus.emit('my-event');
eventBus.emit('my-event', null, 'a', 'b'); // your callback sould be function (a, b) { ... }
eventBus.emit('my-event', new SomeObject, 'a', 'b'); // your callback sould be function (a, b) { ... } and `this` will be set to the context of `SomeObject`
```
#### Detach an event
```js
var callbackForMyEvent = function () {
console.log('Inside `my-event`.');
};
eventBus.on('my-event', callbackForMyEvent);
eventBus.emit('my-event');
eventBus.detach('my-event', callbackForMyEvent);
```
This code will emit the event `my-event` and then detach the given callback for this event. So it'll not be executed anymore.
#### Detach an event for all the callbacks that have been set before
```js
eventBus.detach('my-event');
```
This code will remove the event `my-event` from the event bus.
#### Detach all the events created in the event bus
```js
eventBus.detachAll();
```
This code will remove the event `my-event` from the event bus.
#### Remove an event
```js
eventBus.on('my-event', function () {
console.log('Inside `my-event`.');
});
eventBus.emit('my-event');
eventBus.die('my-event');
```
This code will emit the event `my-event` and then detach all the callbacks for this event. So any of them won't be executed anymore.
Note that `off` is an alias of `die`.
# License
MIT