pluck-stream

pluck-stream

Pluck a property (or properties) from a JSON stream

$ npm install --save pluck-stream

var pluck = require('pluck-stream')
var rs = fs.createReadStream('./package.json')

pluck(rs, 'version', function (err, version) {
  // version = 1.0.0
})

Pluck can also emit events as they are parsed. Just leave out the callback.

pluck(res, 'version').on('version', function (version) {
  // version = 1.0.0
})

This module wraps JSONStream simply to avoid some of the plumbing.

pluck(stream, properties, [callback])

stream

• Type: Stream

The source stream to pluck properties from.

properties

• Type: String, String[]

The accepted notation is the same as documented JSONStream.parse.

callback(err, results)

• Type: Function
• Optional

If a callback is provided, when the stream is ended, the callback is executed with the following parameters.

If a callback is not provided, pluck.stream is automatically engaged.

callback.err

• Type: ?Error

An error that ocurred while parsing the stream. Errors on the source stream need to be listened to independently.

callback.results

• Type: *

If multiple properties were provided, this is a hash of property key -> parsed value. If a single property was given, this is just the value.

pluck.stream(properties...)

• Type: Function
• Returns: Stream

Use this function to get multiple results as they arrive. Events are emitted under the same name as the given property string.

var pluck = require('pluck-stream')
var rs = fs.createReadStream('./package.json')

rs.pipe(pluck.stream('version'))
  .on('version', function(version) {
    // version = 1.0.0
  })

properties...

• Type: String, String[]

All arguments are combined into an array of property strings to parse. The accepted notation is the same as documented JSONStream.parse.