abstract-stream-leveldown
=========================

This library provides a smaller API footprint for using [AbstractLevelDOWN][] to create a [LevelDOWN][] backend, by implementing a [Readable][] and [Writable][] stream instead of all of the [abstract LevelDOWN methods][]. It's a good fit for turning something that already has readable and writable stream interfaces into a LevelDOWN backend.

Example
-------

in es6

```javascript
import {AbstractStreamLevelDOWN} from "abstract-stream-leveldown"

class MyLevelDOWN extends AbstractStreamLevelDOWN {
   _createReadStream([options]) { /* return a Readable */ }
   _createWriteStream([options]) { /* return a Writable */ }
}
```

in es5

```javascript
var inherits = require('inherits')
var assign = require('object-assign')
var AbstractStreamLevelDOWN = require('abstract-stream-leveldown').AbstractStreamLevelDOWN

function MyLevelDOWN (location) {
  AbstractLevelDOWN.call(this, location)
}
inherits(MyLevelDOWN, AbstractStreamLevelDOWN)
assign(AbstractStreamLevelDOWN, {
  _createReadStream([options]) { /* return a Readable */ }
  _createWriteStream([options]) { /* return a Writable */ }
}
```

API
---

### AbstractStreamLevelDOWN#_createReadStream([options])

Returns a [Readable][] stream. `options` should support the same properties as those to be passed to [createReadStream][].

### AbstractStreamLevelDOWN#_createWriteStream([options])

Returns a [Writable][] stream. `options` should support the same properties as those to be passed to [put][]. This stream accepts `{key, value}` objects, and will perform a `del` if the value is null or undefined, and a `put` otherwise.

[AbstractLevelDOWN]: https://github.com/rvagg/abstract-leveldown
[LevelDOWN]: https://github.com/rvagg/node-leveldown
[Readable]: https://iojs.org/api/stream.html#stream_class_stream_readable
[Writable]: https://iojs.org/api/stream.html#stream_class_stream_writable
[abstract LevelDOWN methods]: https://github.com/rvagg/abstract-leveldown#extensible-api
[createReadStream]: https://github.com/rvagg/node-levelup#createReadStream
[put]: https://github.com/rvagg/node-levelup#put