生成器-》详解

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    <script>
        // function* func(){
        //     console.log('A');
        //     yield 1;
        //     console.log('B');
        //     yield 2;
        //     console.log('C');
        //     yield 3;
        //     console.log('D');
        //     return 4;
        // }

        // func.prototype.AA = 10; 
        // let iterator = func(); 
        //  console.log(iterator.next());  // {value: 1, done: false}
        //  console.log(iterator.next());  // {value: 2, done: false}
        //  console.log(iterator.next());  // {value: 3, done: false}
        //  console.log(iterator.next());  // {value: undefined, done: true}


        // function* func(){
        //     let x = yield 1;
        //     console.log(x);
        // }
        // let iterator = func(); 
        // iterator.next()
        // iterator.next(10)


        // function* func1(){
        //     yield 1;
        //     yield 2;
        // }

        // function* func2(){
        //     yield 3;
        //     yield* func1();
        //     yield 4;
        // }

        // let iterator = func2(); 
        // console.log(iterator.next()); 
        // console.log(iterator.next());
        // console.log(iterator.next());
        // console.log(iterator.next());

        const func = x =>{
            return new Promise(resolve=>{
                setTimeout(()=>{
                    resolve(++x);
                },1000);
            })
        }

        // 异步串行
        // func(0).then(x=>{
        //     console.log(x);
        //     return func(x)
        // }).then(x=>{
        //     console.log(x);
        //     return func(x);
        // }).then(x=>{
        //     console.log(x);
        //     return func(x);
        // })

        // (async function(){
        //     let x = await func(0);
        //     console.log(x);

        //     x = await func(x);
        //     console.log(x);

        //     x = await func(x);
        //     console.log(x);
        // })() 
        
        // function* generator(x){
        //     x = yield func(x);
        //     console.log(x);  // 1

        //     x = yield func(x);
        //     console.log(x);  // 2

        //     x = yield func(x);
        //     console.log(x);  // 3
        // }

        // let iterator =  generator(0);
        // let result = iterator.next();
        // result.value.then(x => {
        //   result = iterator.next(x) ;
        //   result.value.then(x => {
        //      result = iterator.next(x) ;
        //      result.value.then(x => {
        //         iterator.next(x) ; 
        //     });
        //   });
        // });


        // 递归实现
        function asyncFunc(generator,...params){
            const iterator = generator(...params);
            const next = x => {
               let {value,done} = iterator.next(x);
               if(done) return ;
               value.then(x => {
                    next(x);
               })
            };
            next();
        }

        asyncFunc(function* (x){
            x = yield func(x);
            console.log(x);  // 1

            x = yield func(x);
            console.log(x);  // 2

            x = yield func(x);
            console.log(x);  // 3
        },0);
    </script> 

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posted @ 2021-07-28 17:59  13522679763-任国强  阅读(26)  评论(0)    收藏  举报