Single Threan Non-Blocking

1. Web APIs
2. Async/Await
3. Callbacks
4. Microtask Queue (Job Queue)
5. Task Queue (Callback Queue)
6. Promises
7. Event loop

setTimeout(()=>{
	console.log("something hello");
},0)
setTimeout(()=>{
  	console.log("somthing world");
},10)
Promise.resolve('hello').then(data=>console.log("data :",data))
console.log(":)")

//call stack
console.log(1) 
setTimeout(()=>{ // Web APIs -> Callback Queue
	console.log(2)
},0)
console.log(3) 
// 1, 3, 2

//1 call stack
//2 call stack -> pop -> web Api -> callback queue -> call stack
//3 call stack 						[event loop]
//empty -------------------------------------------> 

Promise

A promise is an object that may produce a single value some time in the future, Either a resolved value, or a reson that it's not resolved(rejected)

const promise = new Promise((res, rej)=>{
	if(true){
      return res("true")
    }
  	return rej("false")
})
//pending
//resolved or rejected === settled ot fullfiled

promise
  .then(result => console.log(result,1))
  .then(result2 => console.log(result2,2))
  .catch(()=>console.log("error",3))
  .then(result3 => {  	throw Error	})    
             

const urls = [
	...
]
Promise.all(urls.map(url => {
	return fetch(url).then(result => result.json())  
}))
.then(results => console.log(results))
.catch(console.log)
// [{...},{...},{...}...]

Async Await

ES8

const player = async () => {
	const firstMove = await move(100,'l');
	await move(100,'l');
	await move(100,'l');
	await move(100,'l');
  
}

Micro Task Queue

// js > microtask queue  > callback queue

setTimeout(()=>{
	console.log("something hello");
},0)
setTimeout(()=>{ // Callback queue - Task queue
  	console.log("somthing world");
},10)

// micotask queue - job queue ; higher than task queue
Promise.resolve('hello').then(data=>console.log("data :",data))
console.log(":)")

Promise.addSettled([promise, promise])

worker

const worker = new Worker('worker.js');
worker.postMessage("hello~~");

addEventListener('message')