# javascript: unload

Run a piece of code whenever the javascript-process stops/exits/quits. On **browsers, nodejs, electron, react-native**. It also ensures that the exit-function is called only **once**.

You should use this module when your write a npm-library where you dont know in which environments the users will run it.

# What does `unload` handle?

When nodejs:
```js
process.on('beforeExit');
process.on('exit');
process.on('SIGINT'); // catches ctrl+c event
process.on('uncaughtException'); // catches uncaught exceptions
```

When browser:
```js
window.addEventListener('beforeunload'); // closing of normal browser-window
window.addEventListener('unload'); // closed inside of iframe
```

# Usage

Installation:

`npm install unload --save`

Add a function which runs when the process exits:

```javascript
var unload = require('unload');
unload.add(function(){
    console.log('Ouch, I\'m dying.');
});
```

Add and remove the function (It will no longer run when the process exits):

```javascript
var unload = require('unload');
var ret = unload.add(function(){
    console.log('Ouch, I\'m dying.');
});

ret.remove(); // removes the event-handler
```

Run all previously added functions:

```javascript
var unload = require('unload');
unload.add(function(){
    console.log('Ouch, I\'m dying.');
});

unload.runAll();
```

Remove all added functions (They will no longer run when the process exits):
```javascript
var unload = require('unload');
unload.add(function(){
    console.log('Ouch, I\'m dying.');
});

unload.removeAll();
```