# eventbusjs

> Managing events with JavaScript

Latest version **0.2.0** (published 2017-04-06) · MIT license · 0 weekly downloads

## Install

```sh
npm install eventbusjs
pnpm add eventbusjs
yarn add eventbusjs
bun add eventbusjs
```

## Health

**Score 18/100 (F)** — status: abandoned.

Positive: has types package; no vulnerabilities.

Warnings: low downloads; no esm support; pre 1.0.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 0.2.0 |
| Published | 2017-04-06 |
| First published | 2016-03-23 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | separate (@types/eventbusjs) |
| Module format | CommonJS |
| Dependencies | 0 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 434 |
| Author | Krasimir Tsonev |
| Maintainers | krasimir |
| Keywords | event, bus, dispatch, listen |

## Links

- npm: https://www.npmjs.com/package/eventbusjs
- Repository: https://github.com/krasimir/EventBus
- Issues: https://github.com/krasimir/EventBus/issues
- npm.io page: https://npm.io/package/eventbusjs

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## Recent versions

- 0.2.0 (latest) — 2017-04-06
- 0.1.0 — 2016-03-23

## README

# Simple JavaScript class for managing events in JavaScript

## Installation

### In a browser

Download [eventbus.min.js](https://raw.githubusercontent.com/krasimir/EventBus/master/lib/eventbus.min.js) and add it to your page.

### In Node

```
npm i eventbusjs -S
```

And then in your code:

```js
var EventBus = require('eventbusjs');
```

## API

### `addEventListener`

```js
// @type - string
// @callback - function
// @scope - the scope where the @callback is defined
EventBus.addEventListener(type, callback, scope)
```

### `removeEventListener`

```js
// @type - string
// @callback - function
// @scope - the scope where the @callback is defined
EventBus.removeEventListener(type, callback, scope)
```

### `hasEventListener`

```js
// @type - string
// @callback - function
// @scope - the scope where the @callback is defined
EventBus.hasEventListener(type, callback, scope)
```

### `dispatch`

```js
// @type - string
// @target - the caller
// @args - pass as many arguments as you want
EventBus.dispatch(type, target, args ...)
```

### `getEvents`

For debugging purpose, it prints out the added listeners.

```js
EventBus.getEvents()
```

## Usage

```js
function myFunction(event) {
  console.log("myFunction type=" + event.type);
}
EventBus.addEventListener("my_function_event", myFunction);
EventBus.dispatch("my_function_event");
```

## Keeping the scope

```js
var TestClass1 = function() {
  this.className = "TestClass1";
  this.callback = function(event) {
    console.log(this.className + " = type:" + event.type + " / dispatcher:" + event.target.className);
  }
};
var TestClass2 = function() {
  this.className = "TestClass2";
  this.dispatchOurEvent = function() {
    EventBus.dispatch("callback_event", this);
  }
};
var t1 = new TestClass1();
var t2 = new TestClass2();
EventBus.addEventListener("callback_event", t1.callback, t1);
t2.dispatchOurEvent();
```

## Passing additional parameters

```js
var TestClass1 = function() {
  this.className = "TestClass1";
  this.doSomething = function(event, param1, param2) {
    console.log(this.className + ".doSomething");
    console.log("type=" + event.type);
    console.log("params=" + param1 + param2);
    console.log("coming from=" + event.target.className);
  }
};
var TestClass2 = function() {
  this.className = "TestClass2";
  this.ready = function() {
    EventBus.dispatch("custom_event", this, "javascript events", " are really useful");
  }
};

var t1 = new TestClass1();
var t2 = new TestClass2();

EventBus.addEventListener("custom_event", t1.doSomething, t1);
t2.ready();
```

## Example of usage EventBus.removeEventListener

To remove EventListener you have to pass same instance of callback
```js

/* Wrong - callback functions are different instances */
EventBus.addEventListener('EXAMPLE_EVENT', function() {
    console.log('example callback');
});
EventBus.removeEventListener('EXAMPLE_EVENT', function() {
    console.log('example callback');
});

/* Correct - callback function is the same instance */
var handler = function() {
    console.log('example callback');
};
EventBus.addEventListener('EXAMPLE_EVENT', handler);
EventBus.removeEventListener('EXAMPLE_EVENT', handler);
```

---
_Source: https://npm.io/package/eventbusjs · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._