Package Exports

thread-stream
thread-stream/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (thread-stream) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

thread-stream

A streaming way to send data to a Node.js Worker Thread.

install

npm i thread-stream

Usage

'use strict'

const ThreadStream = require('thread-stream')
const { join } = require('path')

const stream = new ThreadStream({
  filename: join(__dirname, 'worker.js'),
  workerData: { dest },
  workerOpts: {}, // Other options to be passed to Worker
  sync: false, // default
})

stream.write('hello')

// Asynchronous flushing
stream.flush(function () {
  stream.write(' ')
  stream.write('world')

  // Synchronous flushing
  stream.flushSync()
  stream.end()
})

In worker.js:

'use strict'

const fs = require('fs')
const { once } = require('events')

async function run (opts) {
  const stream = fs.createWriteStream(opts.dest)
  await once(stream, 'open')
  return stream
}

module.exports = run

Make sure that the stream emits 'close' when the stream completes. This can usually be achieved by passing the autoDestroy: true flag your stream classes.

The underlining worker is automatically closed if the stream is garbage collected.

External modules

You may use this module within compatible external modules, that exports the worker.js interface.

const ThreadStream = require('thread-stream')

const modulePath = require.resolve('pino-elasticsearch')

const stream = new ThreadStream({
  filename: modulePath,
  workerData: { node: 'http://localhost:9200' }
})

stream.write('log to elasticsearch!')
stream.flushSync()
stream.end()

This module works with yarn in PnP (plug'n play) mode too!

Emit events

You can emit events on the ThreadStream from your worker using worker.parentPort.postMessage(). The message (JSON object) must have the following data structure:

parentPort.postMessage({
  code: 'EVENT',
  name: 'eventName',
  args: ['list', 'of', 'args', 123, new Error('Boom')]
})

On your ThreadStream, you can add a listener function for this event name:

const stream = new ThreadStream({
  filename: join(__dirname, 'worker.js'),
  workerData: {},
})
stream.on('eventName', function (a, b, c, n, err) {
  console.log('received:', a, b, c, n, err) // received: list of args 123 Error: Boom
})

License

MIT