# JavaScript SBP Bindings

## Installing from npm

`npm install sbp`

## Building the JavaScript sbp bindings

From the parent directory, run `make javascript` to regenerate bindings.

This library supports and is tested with NodeJS v0.10.x, v0.12.x, v4.x, and v5.x.

## Using the JavaScript sbp bindings
You can include the `javascript/sbp` directory. Two objects are exported - `dispatch` and `decode`
(see `msg.js`). `dispatch` is used to connect to a stream of binary data and `decode` can be used
to parse individual binary messages.packets.

### Requirements
```
pip install tox
brew install nodejs
npm install -g mocha
```

### Examples
See `test_http_stream.js` for connecting an HTTP stream to the dispatcher.

See the minimal [JavaScript map console](https://github.com/JoshuaGross/piksi-console) for an example of connecting Piksi via USB and mapping points with Google Maps.

## JSON schema definitions

Some web clients process SBP that's been converted to JSON (via the `sbp2json`
tool).  To aide in building various web clients, we generate JSON schema
definitions to parse the output of `sbp2json`. This allows web clients to
dispatch on the msg_type field in a JSON dictionary and build a fully native
object using the JSON fields that are present.

For example, in JavaScript, this is be possible:

```js

import { Convert, MsgVelNED} from "./SbpJson";

const json = getJsonBlob();

if (json['msg_type'] === 529) {
    const msgVelNED = Convert.toMsgVelNED(json);
    // ... do stuff with msgVelNED
}
```

The value of this is more fully realized when using a typed language like
TypeScript or Elm.  Fully native objects allow TypeScript and Elm to
type check interactions with the output from `sbp2json`.