# JSONStream

streaming JSON.parse and stringify

## example

```javascript

var request = require('request')
  , JSONStream = require('JSONStream')
  , es = require('event-stream')

var parser = JSONStream.parse(['rows', /./])
  , req = request({url: 'http://isaacs.couchone.com/registry/_all_docs'})
  , logger = es.mapSync(function (data) {
      console.error(data)
      return data
    })
```

in node 0.4.x

``` javascript

req.pipe(parser)
parser.pipe(logger)

```

in node v0.5.x

``` javascript
req.pipe(parser).pipe(logger)

```

## JSONStream.parse(path)

usally, a json API will return a list of objects.  

`path` should be an array of property names and/or `RedExp`s.  
any object that matches the path will be emitted as 'data' (and `pipe`d down stream)

if `path` is empty or null, or if no matches are made:  
JSONStream.parse will only one 'data': the root object.

(this is useful when there is an error, because the error will probably not match your path)

### example

query a couchdb view:

``` bash
curl -sS localhost:5984/tests/_all_docs&include_docs=true
```
you will get something like this:

``` js
{"total_rows":129,"offset":0,"rows":[
  { "id":"change1_0.6995461115147918"
  , "key":"change1_0.6995461115147918"
  , "value":{"rev":"1-e240bae28c7bb3667f02760f6398d508"}
  , "doc":{
      "_id":  "change1_0.6995461115147918"
    , "_rev": "1-e240bae28c7bb3667f02760f6398d508","hello":1}
  },
  { "id":"change2_0.6995461115147918"
  , "key":"change2_0.6995461115147918"
  , "value":{"rev":"1-13677d36b98c0c075145bb8975105153"}
  , "doc":{
      "_id":"change2_0.6995461115147918"
    , "_rev":"1-13677d36b98c0c075145bb8975105153"
    , "hello":2
    }
  },
]}

```

we are probably most interested in the `rows.*.docs`  

create a `Stream` that parses the documents from the feed like this:

``` js
JSONStream.parse(['rows', /./, 'doc']) //rows, ANYTHING, doc
``` 
awesome!

## JSONStream.stringify(open, sep, close)

Create a writable stream.

you may pass in custom `open`, `close`, and `seperator` strings.  
But, by default, `JSONStream.stringify()` will create an array,  
(with default options `open='[\n', sep='\n,\n', cl='\n]\n'`)

If you call `JSONStream.stringify(false)`   
the elements will only be seperated by a newline.  

If you only write one item this will be valid JSON.  

If you write many items,  
you can use a `RegExp` to split it into valid chunks.

## numbers

There are occasional problems parsing and unparsing very precise numbers.  

I have opened an issue here:

https://github.com/creationix/jsonparse/issues/2

+1

## Acknowlegements

this module depends on https://github.com/creationix/jsonparse  
by Tim Caswell  
and also thanks to Florent Jaby for teaching me about parsing with:
https://github.com/Floby/node-json-streams