SOURCE

const setTime = (val, m) =>
  new Promise((resolve) => {
    setTimeout(() => {
        resolve(val)
    }, m)
  }).then((e) => {
      console.log(e);
      return e;
  })

const func1 = () => setTime(1, 2000)
const func2 = () => setTime(2, 1000)
const func3 = () => setTime(3, 2000)

//实现一个函数

function exectudePromise(list = []) {
    return new Promise((resolve) => {
        const newList = [];
        function *func(){
            for(let i = 0, len = list.length; i < len; i++){
                const val = yield list[i]().then(a => res.next(a));
                newList.push(val);
            };
            resolve(newList)
        }
        var res = func();
        res.next();
    })
}

exectudePromise([func1, func2, func3]).then((res) => {
  console.log('end')
  console.log(res)
})