面试题：JavaScript中async和await的基本使用

Question

请编写一个JavaScript函数，使用async和await来实现依次调用三个异步函数（可以用setTimeout模拟异步操作），并且将每个异步函数的返回值依次打印出来。假设这三个异步函数分别为asyncFunction1、asyncFunction2、asyncFunction3，它们返回Promise对象，且Promise对象resolve的值分别为'result1'、'result2'、'result3'。

Answer 1

function asyncFunction1() {
    return new Promise((resolve) => {
        setTimeout(() => {
            resolve('result1');
        }, 1000);
    });
}

function asyncFunction2() {
    return new Promise((resolve) => {
        setTimeout(() => {
            resolve('result2');
        }, 1000);
    });
}

function asyncFunction3() {
    return new Promise((resolve) => {
        setTimeout(() => {
            resolve('result3');
        }, 1000);
    });
}

async function callFunctionsSequentially() {
    try {
        const result1 = await asyncFunction1();
        console.log(result1);
        const result2 = await asyncFunction2();
        console.log(result2);
        const result3 = await asyncFunction3();
        console.log(result3);
    } catch (error) {
        console.error(error);
    }
}

callFunctionsSequentially();