synckit

What is synckit?

The synckit npm package allows for executing asynchronous tasks synchronously using worker threads or child processes. It is designed to offload heavy computation or I/O-bound tasks without blocking the main thread, thus enabling a synchronous-like coding style while maintaining non-blocking behavior.

What are synckit's main functionalities?

Running asynchronous tasks synchronously

This feature allows you to run an asynchronous task inside a worker thread and wait for the result synchronously. The 'worker.js' file should export an async function that will be executed with the provided arguments.

const { runAsWorkerThread } = require('synckit');
const result = runAsWorkerThread('./worker.js', ...args);

Creating a synchronous API from asynchronous functions

With this feature, you can create a synchronous version of an asynchronous function. The 'async-fn.js' file should export an async function that will be executed with the provided arguments, and the result will be returned synchronously.

const { createSyncFn } = require('synckit');
const syncFn = createSyncFn('./async-fn.js');
const result = syncFn(...args);

Other packages similar to synckit

deasync

Deasync turns asynchronous functions into synchronous by blocking the event loop. It is similar to synckit in providing a way to write synchronous-style code, but it does so by pausing the event loop, which can lead to performance issues and is not recommended for production use.

threads

The 'threads' package is used to manage and work with Web Workers and worker threads in Node.js. It offers similar functionality to synckit by allowing asynchronous tasks to be offloaded to separate threads, but it provides a more comprehensive API for managing those threads.

workerpool

Workerpool is a package for managing a pool of workers and running tasks in parallel. It is similar to synckit in that it uses worker threads to execute tasks asynchronously, but it focuses on managing a pool of workers and distributing tasks among them for parallel processing.

README

synckit

Perform async work synchronously in Node.js using worker_threads, or child_process as fallback, with first-class TypeScript support.

TOC

• Usage
  • Install
  • API
  • Env variables
  • TypeScript
• Benchmark
• Changelog
• License

Usage

Install

# yarn
yarn add synckit

# npm
npm i synckit

API

worker_threads is used by default for performance, if you have any problem with it, you can set env SYNCKIT_WORKER_THREADS=0 to disable it and fallback to previously child_process solution, and please raise an issue here so that we can improve it.

// runner.js
import { createSyncFn } from 'synckit'

// the worker path must be absolute
const syncFn = createSyncFn(require.resolve('./worker'))

// do whatever you want, you will get the result synchronously!
const result = syncFn(...args)

// worker.js
import { runAsWorker } from 'synckit'

runAsWorker(async (...args) => {
  // do expensive work
  return result
})

You must make sure:

1. if worker_threads is enabled (by default), the result is serialized by Structured Clone Algorithm
2. if child_process is used, the result is serialized by JSON.stringify

Env variables

1. SYNCKIT_WORKER_THREADS: whether or not enable worker_threads, it's enabled by default, set as 0 to disable
2. SYNCKIT_BUFFER_SIZE: bufferSize to create SharedArrayBuffer for worker_threads (default as 1024), or maxBuffer for child_process (no default)
3. SYNCKIT_TIMEOUT: timeout for performing the async job (no default)

TypeScript

If you want to use ts-node for worker file (a .ts file), it is supported out of box!

If you want to use a custom tsconfig as project instead of default tsconfig.json, use TS_NODE_PROJECT env. Please view ts-node for more details.

If you want to integrate with tsconfig-paths, please view ts-node for more details.

Benchmark

It is about 20x faster than sync-threads but 3x slower than native for reading the file content itself 1000 times during runtime, and 18x faster than sync-threads but 4x slower than native for total time.

And it's almost same as deasync but requires no native bindings or node-gyp.

See benchmark for more details.

You can try it with running yarn benchmark by yourself. Here is the benchmark source code.

Changelog

Detailed changes for each release are documented in CHANGELOG.md.

License

MIT © [e-mail]