synckit

Perform async work synchronously in Node.js using worker_threads with first-class TypeScript support.

Usage

Install

# yarn
yarn add synckit

# npm
npm i synckit

API

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

// the worker path must be absolute
const syncFn = createSyncFn(require.resolve('./worker'), {
  tsRunner: 'tsx', // optional, can be `'ts-node' | 'esbuild-register' | 'esbuild-runner' | 'tsx'`
})

// 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, the result is serializable by Structured Clone Algorithm

Options

bufferSize same as env SYNCKIT_BUFFER_SIZE
timeout same as env SYNCKIT_TIMEOUT
execArgv same as env SYNCKIT_EXEC_ARGV
tsRunner same as env SYNCKIT_TS_RUNNER

Envs

SYNCKIT_BUFFER_SIZE: bufferSize to create SharedArrayBuffer for worker_threads (default as 1024)
SYNCKIT_TIMEOUT: timeout for performing the async job (no default)
SYNCKIT_EXEC_ARGV: List of node CLI options passed to the worker, split with comma ,. (default as []), see also node docs
SYNCKIT_TS_RUNNER: Which TypeScript runner to be used, it could be very useful for development, could be 'ts-node' | 'esbuild-register' | 'esbuild-runner' | 'swc' | 'tsx', 'ts-node' is used by default, make sure you have installed them already

TypeScript

`ts-node`

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.

`esbuild-register`

Please view esbuild-register for its document

`esbuild-runner`

Please view esbuild-runner for its document

`swc`

Please view @swc-node/register for its document

`tsx`

Please view tsx for its document

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.cjs and benchmark.esm for more details.

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