32-异步方案与Node

码路教育 9/13/2001

# 一. 下面程序输入结果是？

<script>
    console.log("script start")

    function requestData(url) {
        console.log("requestData")
        return new Promise((resolve) => {
            setTimeout(() => {
                console.log("setTimeout")
                resolve(url)
            }, 2000);
        })
    }
    async function getData() {
        console.log("getData start")
        const res = await requestData("wc")

        console.log("then1-res:", res)
        console.log("getData end")
    }
    getData()

    console.log("script end")
</script>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

# 二. 下面程序输入结果是？

<script>
    console.log("script start")
    setTimeout(function() {
        console.log("setTimeout1");
        new Promise(function(resolve) {
            resolve();
        }).then(function() {
            new Promise(function(resolve) {
                resolve();
            }).then(function() {
                console.log("then4");
            });
            console.log("then2");
        });
    });
    new Promise(function(resolve) {
        console.log("promise1");
        resolve();
    }).then(function() {
        console.log("then1");
    });
    setTimeout(function() {
        console.log("setTimeout2");
    });
    console.log(2);
    new Promise(function(resolve) {
        resolve();
    }).then(function() {
        console.log("then3");
    });
    console.log("script end")
</script>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

# 三. 下面程序输入结果是？

async function async1() {
    console.log('async1 start')
    await async2()
    console.log('async1 end')
}

async function async2() {
    console.log('async2')
}

console.log('script start')

setTimeout(function() {
    console.log('setTimeout0')
}, 0)

setTimeout(function() {
    console.log('setTimeout2')
}, 300)

async1();

new Promise(function(resolve) {
    console.log('promise1')
    resolve();
    console.log('promise2')
}).then(function() {
    console.log('promise3')
})

console.log('script end')

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

# 四. 下面程序输入结果是？

<script>
    async function async1() {
        console.log('async1 start')
        await async2();
        console.log('async1 end')
    }

    async function async2() {
        console.log('async2')
    }

    console.log('script start')

    setTimeout(function() {
        console.log('setTimeout')
    }, 0)

    async1();

    new Promise(function(resolve) {
        console.log('promise1')
        resolve();
    }).then(function() {
        console.log('promise2')
    })
    console.log('script end')
</script>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

# 五. 下面程序输入结果是？（选做）

自行研究

<script>
    Promise.resolve().then(() => {
        console.log(0);
        return {
            then: function(resolve, reject) {
                resolve(4)
            }
        };
    }).then((res) => {
        console.log(res)
    })

    Promise.resolve().then(() => {
        console.log(1);
    }).then(() => {
        console.log(2);
    }).then(() => {
        console.log(3);
    }).then(() => {
        console.log(5);
    }).then(() => {
        console.log(6);
    })
</script>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

# 六. 下面程序输入结果是？（选做）

自行研究

<script>
    Promise.resolve().then(() => {
        console.log(0);
        return Promise.resolve(4);
    }).then((res) => {
        console.log(res)
    })

    Promise.resolve().then(() => {
        console.log(1);
    }).then(() => {
        console.log(2);
    }).then(() => {
        console.log(3);
    }).then(() => {
        console.log(5);
    }).then(() => {
        console.log(6);
    })
</script>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

# 七. 安装Node，NVM，NRM（必做）

# 八. 说一下，你对CommonJS模块化的理解

31-异步方案 33-模块化与网络