function-threads

Function Threads

Additional layer for Node.js "worker_threads" module.

Library provides run function, which takes a callback as an argument, runs it in a thread and returns a promise. Inside callback you can return promise or plain value(i.e. object, string and etc...).

Installation

Using npm:

$ npm i --save function-threads

Using yarn:

$ yarn add function-threads

Example

Make sure you're using Node.js >= v10.5.0

And always use --experimental-worker flag when you run project, because worker-threads has been implemented under the hood which is in Experimental mode.

$ node --experimental-worker  index.js

Example basic/index.js:

const Thread = require('function-threads');

Thread.run(() => 2 ** 10)
  .then((num) => {
    console.log(`Result: ${num}`);
  })
  .catch((err) => {
    console.error(err);
  });

All examples:

• Basic
• Run thread with custom data
• Async thread
• Error handling
• Work with FileSystem

API

Thread.run()

Parameters

(Function): Returns Promise, you can use async/await or just then/catch to get value.

(object/array or primitive value): You can send custom data which will be used in a thread. You can acces to this data using global.threadData in function.

Returns

(Promise): Returns Promise, you can use async/await or just then/catch to get value.

Important

You can't access to any data outside of function, if you need to use a module, you should
require it in a callback. The only way to access data in a callback from outside is the useage
of second parameter. Closures will not work here.

Example

Work wit FileSystem index.js:

const Thread = require('function-threads');

const customData = {
  fileName: 'test.txt',
};

Thread.run(async () => {
  const fs = require('fs');
  const fsPromises = fs.promises;

  const { fileName } = global.threadData;

  await fsPromises.writeFile(fileName, '');

  return true;
}, customData)
  .then((res) => {
    console.log(`Success: ${res}`);
  })
  .catch((err) => {
    console.error(err);
  });

And don't forgot to use Node >= v10.5.0 and --experimental-worker flag.

$ node --experimental-worker  index.js