Javascript async

promise

Promise.all(iterable) 全部， 一个失败就停止

Promise.allSettled(iterable) 全部，即使有失败也不停止

Promise.any(iterable) 一个成功就停止

Promise.race(iterable) 一个成功或失败就停止

thunk 实现

const Thunk=(fn)=>{
    return function(){
        var args = Array.prototype.slice.call(arguments);
        return function (callback){
            args.push(callback);
            return fn.apply(this,args);
        }
    }
}

const readFile = (data, callback) => {
    setTimeout(() => {
        callback(data)
    }, 1000)
}

const readFileThunk = Thunk(readFile);
readFileThunk('fileName')((data) => {
    console.log('data', data);
})

generate function

function* gen(x){
    var y = yield x + 2;
    return y;
}

var g = gen(1);
const result1= g.next()
console.log(result1) // { value: 3, done: false }
const result2 = g.next(1)
console.log(result2); // { value: 1, done: true }

co

event loop

https://www.ruanyifeng.com/blog/2014/10/event-loop.html

microtask macrotask

setTimeout(() => alert("timeout"));

Promise.resolve()
  .then(() => alert("promise"));

alert("code");

// code
// promise
// timeout

console.log(1);
setTimeout(() => console.log(2));
Promise.resolve().then(() => console.log(3));
Promise.resolve().then(() => setTimeout(() => console.log(4)));
Promise.resolve().then(() => console.log(5));
setTimeout(() => console.log(6));
console.log(7);
// 1 7 3 5 2 6 4