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Intro

At the highest level of its design, Concurrent.js is a dynamic module importer like require and import. But instead of loading a module into the main thread, it loads the module into a background thread. Concurrent.js helps with non-blocking computation on JavaScript RTEs and also provides a foreign function interface to other languages in order to achieve better performance and richer computational libraries.

Sponsors

If you are interested in sponsoring the project, please contact us at hello@bitair.org.

Features

• Platform/Language support
  • Web browsers
    • JavaScript (ECMAScript & CommonJS)
    • WebAssembly
  • Node.js
    • JavaScript (ECMAScript & CommonJS)
    • C
    • C++
    • Go
    • Java
    • Python
    • Ruby
    • Rust
    • TypeScript
    • WebAssembly
  • Deno
    • JavaScript (ECMAScript & CommonJS)
    • C
    • C++
    • Go
    • Java
    • Python
    • Ruby
    • Rust
    • TypeScript
    • WebAssembly
• Parallel execution
• Reactive concurrency
• Inter-worker data sharing
• Multithreaded dependency resolver
• Sandboxing

Technical facts

• Built upon web workers (a.k.a. worker threads).
• Creates a worker once and reuses it.
• Automatically cleans up a worker’s memory.
• Automatically creates and terminates workers.
• Has no third-party runtime dependency.
• Written in TypeScript with the strictest ESNext config.
• Strictly designed to support strongly-typed programming.
• Packaged as platform-specific bundles that target ES2020.

Hello World!

Save and run the hello world script to see it in action:

bash hello_world.sh

Usage

Running JavaScript

import { concurrent } from '@bitair/concurrent.js'

// import and load a JS module into a worker
const { SampleObject, sampleFunction } = await concurrent.import('sample-js-module.js').load()

// run a function
const result = await sampleFunction(/*...args*/)

// run a class (instance members)
const obj = await new SampleObject(/*...args*/) // instantiate
const value = await obj.sampleProp // get a field or getter
await ((obj.sampleProp = 1), obj.sampleProp) // set a field or setter
const result = await obj.sampleMethod(/*...args*/) // call a method

// run a class (static members)
const value = await SampleObject.sampleStaticProp // get a static field or getter
await ((SampleObject.sampleStaticProp = 1), SampleObject.sampleStaticProp) // set a static field or setter
const result = await SampleObject.sampleStaticMethod(/*...args*/) // call a static method

// terminate Concurrent.js
await concurrent.terminate()

Running WebAssembly

import { concurrent } from '@bitair/concurrent.js'
const { sampleFunction } = await concurrent.import('sample-wasm-module.wasm').load()
const result = await sampleFunction(/*...args*/)
await concurrent.terminate()

Running C, C++, Go and Rust

This feature requires the Linker.c package to be manually installed.

import { concurrent, ExternFunctionReturnType } from '@bitair/concurrent.js'
const { sampleFunction } = await concurrent
  .import('shared-lib.so', {
    extern: {
      sampleFunction: ExternFunctionReturnType.Number
    }
  })
  .load()
const result = await sampleFunction(/*...args*/)
await concurrent.terminate()

Projects

If you have built a project that uses Concurrent.js and you want to list it here, please email its details to hello@bitair.org.

• Browser

  • Basic usage (Sample)
  • Basic interop with WASM (Sample)
  • Integration with Tensorflow (Sample)

• Node

  • Basic usage (Sample)

• Deno

  • Basic usage (Sample)

Sample

Node.js (ECMAScript)

npm i @bitair/concurrent.js@latest

index.js

import { concurrent } from '@bitair/concurrent.js'
const { factorial } = await concurrent.import('extra-bigint').load()
const result = await factorial(50n)
console.log(result)
await concurrent.terminate()

package.json

{
  "type": "module",
  "dependencies": {
    "@bitair/concurrent.js": "^0.7.0",
    "extra-bigint": "^1.1.10"
  }
}

node .

Deno

index.ts

import { concurrent } from 'https://deno.land/x/concurrentjs@v0.7.0/mod.ts'
const { factorial } = await concurrent.import(new URL('services/index.ts', import.meta.url)).load()
const result = await factorial(50n)
console.log(result)
await concurrent.terminate()

services/index.ts

export { factorial } from 'extra-bigint'

deno.json

{
  "imports": {
    "extra-bigint": "npm:extra-bigint@^1.1.10"
  }
}

deno run --allow-read --allow-net index.ts

Browser

.
├── src
    ├── services
        ├── index.js
    ├── app.js
    ├── worker_script.js
    .
├── static
    ├── index.html
.

app.js

import { concurrent } from '@bitair/concurrent.js'
const { factorial } = await concurrent.import(new URL('services/index.js', import.meta.url)).load()
const result = await factorial(50n)
console.log(result)
await concurrent.terminate()

services/index.js

export { factorial } from 'extra-bigint'

worker_script.js

import '@bitair/concurrent.js/worker_script'

index.html

<!DOCTYPE html>
<html>
  <body>
    <script type="module" src="scripts/main.js"></script>
  </body>
</html>

build.sh

#!/bin/bash
npx esbuild src/app.js --bundle --format=esm --platform=browser --target=esnext --outfile=static/scripts/main.js
npx esbuild src/worker_script.js --bundle --format=esm --platform=browser --target=esnext --outfile=static/scripts/worker_script.js
npx esbuild src/services/index.js --bundle --format=esm --platform=browser --target=esnext --outfile=static/scripts/services/index.js

package.json

{
  "type": "module",
  "dependencies": {
    "@bitair/concurrent.js": "^0.7.0",
    "http-server": "^14.1.1",
    "extra-bigint": "^1.1.10"
  },
  "devDependencies": {
    "esbuild": "^0.17.8"
  }
}

bash ./build.sh && npx http-server static

Parallelism

import { concurrent } from '@bitair/concurrent.js'

const extraBigint = concurrent.import('extra-bigint')

concurrent.config({ maxThreads: 16 }) // Instead of a hardcoded value use os.availableParallelism() in Node.js v19.4.0 or later

const ops = []
for (let i = 0; i <= 100; i++) {
  const { factorial } = await extraBigint.load()
  ops.push(factorial(i))
}

const results = await Promise.all(ops)
// ...rest of the code

await concurrent.terminate()

API

concurrent.import<T>(src: URL | string, options?: ModuleImportOptions): IConcurrentModule<T>

Imports and prepares the module for being loaded into workers. Note that only functions and classes can be imported. Importing and accessing classes only works on JavaScript and TypeScript languages.

• src: URL | string

  Source of the module. Must be either a URL or a package name. Note that passing a package name is only applicable in Node.js.

• options?: ModuleImportOptions

  • ModuleImportOptions

    type ModuleImportOptions = Partial<{
      extern: {
        [key: string]: ExternFunctionReturnType
      }
    }>

    • ExternFunctionReturnType

      enum ExternFunctionReturnType {
        ArrayBuffer,
        Boolean,
        Number,
        String
      }

IConcurrentModule<T>.load() : Promise<T>

Loads the module into a worker.

concurrent.config(settings: ConcurrencySettings): void

Configs the global settings of Concurrent.js.

• settings: ConcurrencySettings

  • settings.maxThreads: number [default=1]

    The max number of available threads to be spawned.

  • settings.threadIdleTimeout: number | typeof Infinity [default=Infinity]

    Number of minutes that Concurrent.js would be waiting before terminating an idle thread.

  • settings.minThreads: number [default=0]

    The number of threads that must be created when Concurrent.js starts and also kept from being terminated when are idle.

concurrent.terminate(force?: boolean): Promise<void>

Terminates Concurrent.js.

• force?: boolean [Not implemented]

  Forces Concurrent.js to exit immediately without waiting for workers to finish their tasks.

License

MIT License