function asyncToGen(genFunction) {
  return function (...args) {
    const gen = genFunction.apply(this, args);
    return new Promise((resolve, reject) => {
      function step(key, arg) {
        let genResult;
        try {
          genResult = gen[key](arg);
        } catch (err) {
          return reject(err);
        }
        const { value, done } = genResult;
        if (done) {
          return resolve(value);
        }
        return Promise.resolve(value).then(
          (val) => {
            step('next', val);
          },
          (err) => {
            step('throw', err);
          },
        );
      }
      step('next');
    });
  };
}
const getData = () => new Promise(resolve => setTimeout(() => resolve('data'), 1000));
function* testG() {
  const data = yield getData();
  console.log('data: ', data);
  const data2 = yield getData();
  console.log('data2: ', data2);
  return 'success';
}

const gen = asyncToGen(testG);
gen().then(res => console.log(res));

let delay = function (time, fnc) {
	setTimeout(() => {
		fnc(time);
	}, time);
}

let promisefy = (fn) => {
	return (...arg) => {
		return new Promise ((resolve, reject)=> {
			fn(...arg, (param)=>{
				resolve(param);
			})
		});
	}
}

let delayP = promisefy(delay);

const gen = function* () {
	const ret1 = yield delayP(1000);
	console.log(ret1);
	const ret2 = yield delayP(2000);
	console.log(ret2);
}

// 阴间写法
const g = gen();
g.next().value.then((res1)=>{
	g.next(res1).value.then((res2)=>{
		//
	});
})


// 正常写法
function co (generator) {
	return new Promise((resolve, reject)=>{
		const gen = generator();
		function next (...param) {
			let tmp = gen.next(...param);
			if (tmp.done) {
				resolve(tmp.value);
				return;
			}
			tmp.value.then((...ret)=>{
				next(...ret);
			})
		}
		next();
	})
}

co(gen).then((res)=>{
    console.log(res);
})