# pull-hash

crypto hash API using [pull-stream][]s

```js
var hash = require('pull-hash')
var pull = require('pull-stream')

pull(
  source,
  hash('sha256', 'hex', function (err, sum) {
	console.log('shasum:', sum)
  }),
  pull.drain()
)
```

## API

```js
var hash = require('pull-hash')
```
#### `hash(type[, encoding], onEnd): through`

Create a through stream that hashes the data and calls `onEnd` when it is done.

- `type`: `crypto.Hash` object, or string to pass to `crypto.createHash`, e.g.
  `"sha256"`
- `encoding`: encoding for the digest to pass to `Hash.digest()`
- `onEnd(err, digest)`: callback with digest when stream is ended or errored

### Extras

```js
var gitHash = require('pull-hash/ext/git')
```
#### `gitHash(object[, encoding], onEnd): through`

Get a git object id.

- `object.type`: one of `["commit", "tree", "blob", "tag"]`
- `object.length || object.size`: size in bytes of the git object's data

```js
var ssbHash = require('pull-hash/ext/ssb')
```
#### `ssbHash(onEnd): through`

Get a hash id of a secure-scuttlebutt blob.

[secure-scuttlebutt]: https://github.com/ssbc/secure-scuttlebutt
[pull-stream]: https://github.com/dominictarr/pull-stream

## License

Copyright (c) 2016 Charles Lehner

Usage of the works is permitted provided that this instrument is
retained with the works, so that any entity that uses the works is
notified of this instrument.

DISCLAIMER: THE WORKS ARE WITHOUT WARRANTY.