# synckit
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[](https://www.npmjs.com/package/synckit)
[](https://github.com/un-ts/synckit/releases)
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Perform async work synchronously in Node.js using `worker_threads` with first-class TypeScript support.
## TOC <!-- omit in toc -->
- [Usage](#usage)
- [Install](#install)
- [API](#api)
- [Options](#options)
- [Envs](#envs)
- [TypeScript](#typescript)
- [`ts-node`](#ts-node)
- [`esbuild-register`](#esbuild-register)
- [`esbuild-runner`](#esbuild-runner)
- [`swc`](#swc)
- [`tsx`](#tsx)
- [Benchmark](#benchmark)
- [Sponsors](#sponsors)
- [Backers](#backers)
- [Changelog](#changelog)
- [License](#license)
## Usage
### Install
```sh
# yarn
yarn add synckit
# npm
npm i synckit
```
### API
```js
// 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)
```
```js
// 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`](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm)
### Options
1. `bufferSize` same as env `SYNCKIT_BUFFER_SIZE`
2. `timeout` same as env `SYNCKIT_TIMEOUT`
3. `execArgv` same as env `SYNCKIT_EXEC_ARGV`
4. `tsRunner` same as env `SYNCKIT_TS_RUNNER`
### Envs
1. `SYNCKIT_BUFFER_SIZE`: `bufferSize` to create `SharedArrayBuffer` for `worker_threads` (default as `1024`)
2. `SYNCKIT_TIMEOUT`: `timeout` for performing the async job (no default)
3. `SYNCKIT_EXEC_ARGV`: List of node CLI options passed to the worker, split with comma `,`. (default as `[]`), see also [`node` docs](https://nodejs.org/api/worker_threads.html)
4. `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](https://github.com/TypeStrong/ts-node#tsconfig) for more details.
If you want to integrate with [tsconfig-paths](https://www.npmjs.com/package/tsconfig-paths), please view [ts-node](https://github.com/TypeStrong/ts-node#paths-and-baseurl) 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`](https://github.com/lambci/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`](https://github.com/abbr/deasync) but requires no native bindings or `node-gyp`.
See [benchmark.cjs](./benchmarks/benchmark.cjs.txt) and [benchmark.esm](./benchmarks/benchmark.esm.txt) for more details.
You can try it with running `yarn benchmark` by yourself. [Here](./benchmarks/benchmark.js) is the benchmark source code.
## Sponsors
| 1stG | RxTS | UnTS |
| ---------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| [](https://opencollective.com/1stG) | [](https://opencollective.com/rxts) | [](https://opencollective.com/unts) |
## Backers
| 1stG | RxTS | UnTS |
| -------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- |
| [](https://opencollective.com/1stG) | [](https://opencollective.com/rxts) | [](https://opencollective.com/unts) |
## Changelog
Detailed changes for each release are documented in [CHANGELOG.md](./CHANGELOG.md).
## License
[MIT][] © [JounQin][]@[1stG.me][]
[`esbuild-register`]: https://github.com/egoist/esbuild-register
[`esbuild-runner`]: https://github.com/folke/esbuild-runner
[`@swc-node/register`]: https://github.com/swc-project/swc-node/tree/master/packages/register
[`tsx`]: https://github.com/esbuild-kit/tsx
[1stg.me]: https://www.1stg.me
[jounqin]: https://GitHub.com/JounQin
[mit]: http://opensource.org/licenses/MIT