esthread v1.3.0

ESThread

modern worker threading library

Usage

browser

<script src="https://unpkg.com/esthread"></script>
<script>
// any task.
// const thread = new Thread(function(a,b){return a+b})
</script>

or esmodule

<script type="module">
import Thread from 'https://unpkg.com/esthread/dist/thread.mjs'
// any task.
// const thread = new Thread(function(a,b){return a+b})
</script>

or npm module

npm install esthread --save

and

import Thread from 'esthread'
// const thread = new Thread(function(a,b){return a+b})

Example1 Simple

const thread = new Thread((a,b)=>a+b)
thread.execute(2,3).then(result=>console.log(result))
  .then(()=>thread.terminate())
  .catch(()=>thread.terminate())

Example2-a with progress.

const thread2a = new Thread((async function(v){
  let sum = 0
  for(let i=v;i>=0;i--){
    await new Promise(res=>setTimeout(res,1000))
    this.emit('count',i) // <-------------
    sum+=i
  }
  return sum
}))
thread2a.on('count',(n)=>console.info(n))
thread2a.execute(10).then(n=>{
  console.log(n)
  thread2a.terminate()
})

Example2-b with progress. if use arrow function task , can't modify this args. should use scoped emit function.

// if use typescript: declare function emit(type:string,data?:any):void
const thread2b = new Thread((async (v)=>{
  let sum = 0
  for(let i=v;i>=0;i--){
    await new Promise(res=>setTimeout(res,1000))
    emit('count',i) // <------------
    sum+=i
  }
  return sum
}))
thread2b.on('count',(n)=>console.info(n))
thread2b.execute(10).then(n=>{
  console.log(n)
  thread2a.terminate()
})

Example3 cloned thread.

// blocking slow function.
function fibonacci(n){
  return n<2 ? n : ( fibonacci(n-1) + fibonacci(n-2) )
}
const [thread3a,thread3b,thread3c] = new Thread(fibonacci).clone(3)
thread3a.once(40).then(result=>console.log(result))
thread3b.once(42).then(result=>console.log(result))
thread3c.once(44).then(result=>console.log(result))

Example4 transferable ArrayBuffer. like webworker.postMessage

const thread4 = new Thread(buffer=>{
  buffer.set([192,168,10,3])
  return buffer
})
const input = new Uint32Array(256)
thread4.execute(input,[input.buffer]).then(output=>{
  // input was transfered. ( can not access from sender )
  console.log(output)
})

Example5 transferable OffscreenCanvas [experimental technology]

const canvas = document.createElement('canvas')
document.body.appendChild(canvas)
const renderer = new Thread((canvas)=>{
  const ctx = canvas.getContext('2d')
  ctx.fillStyle = 'rgb(200, 0, 0)'
  ctx.fillRect(20, 30, 60, 40)
  ctx.commit()
})
const offscreen = canvas.transferControlToOffscreen() // NOTE: OffscreenCanvas required explicitly enable this feature 2018.3.
renderer.execute( offscreen , [offscreen] )

Example6 with other libraries

async function learn(){
  // foo bar
}
const thread6 = new Thread(learn,['https://cdn.jsdelivr.net/npm/setimmediate@1.0.5/setImmediate.min.js'])

Example7 NodeJS Worker [experimental technology] ( nodejs > v10.5.0 )

node --experimental-worker examples/nodejs/example3.js

const { Thread } = require('esthread')

function fibonacci(n){
  // if need other library. you can use require('some library') here.
  return n<2 ? n : ( fibonacci(n-1) + fibonacci(n-2) )
}
const [thread3a,thread3b,thread3c] = new Thread(fibonacci).clone(3)
thread3a.once(37).then(result=>console.log(result))
thread3b.once(39).then(result=>console.log(result))
thread3c.once(41).then(result=>console.log(result))