# pump

pump is a small node module that pipes streams together and destroys all of them if one of them closes.

```
npm install pump
```

[![build status](http://img.shields.io/travis/mafintosh/pump.svg?style=flat)](http://travis-ci.org/mafintosh/pump)

## What problem does it solve?

When using standard `source.pipe(dest)` source will _not_ be destroyed if dest emits close or an error.
You are also not able to provide a callback to tell when then pipe has finished.

pump does these two things for you

## Usage

Simply pass the streams you want to pipe together to pump and add an optional callback

```js
var pump = require("pump");
var fs = require("fs");

var source = fs.createReadStream("/dev/random");
var dest = fs.createWriteStream("/dev/null");

pump(source, dest, function (err) {
  console.log("pipe finished", err);
});

setTimeout(function () {
  dest.destroy(); // when dest is closed pump will destroy source
}, 1000);
```

You can use pump to pipe more than two streams together as well

```js
var transform = someTransformStream();

pump(source, transform, anotherTransform, dest, function (err) {
  console.log("pipe finished", err);
});
```

If `source`, `transform`, `anotherTransform` or `dest` closes all of them will be destroyed.

Similarly to `stream.pipe()`, `pump()` returns the last stream passed in, so you can do:

```
return pump(s1, s2) // returns s2
```

If you want to return a stream that combines _both_ s1 and s2 to a single stream use
[pumpify](https://github.com/mafintosh/pumpify) instead.

## License

MIT

## Related

`pump` is part of the [mississippi stream utility collection](https://github.com/maxogden/mississippi) which includes more useful stream modules similar to this one.
