顺序 function 调用

Question

我有一个异步函数数组，要按顺序调用，前面function的调用结果传入arguments。 大约如何做到这一点？

Answer 1

// lets say we have a function that takes a value and adds 20 to it asynchronously
const asyncPlus20 = num => Promise.resolve(num+a)
const arr = [asyncPlus20, asyncPlus20]

let res = 0 // some starting value
for (const f of arr) res = await f(res)
// res is now 20

Answer 2

异步函数数组的最佳方法之一是使用For...of 。

在控制台中运行以下代码段。 >> 还包括参数传递

const twoSecondsPromise = () => {
    return new Promise((resolve) => {
        setTimeout(() => resolve('2000_'), 2000);
    })
};

const threeSecondsPromise = (val) => {
    return new Promise((resolve) => {
        setTimeout(() => resolve(val + '3000_'), 3000);
    })
};

const fiveSecondsPromise = (val) => {
    return new Promise((resolve) => {
        setTimeout(() => resolve(val + '5000_'), 5000);
    })
};

(async function () {
    const asyncFunctions = [twoSecondsPromise, threeSecondsPromise, fiveSecondsPromise];
    let result;
    for (const file of asyncFunctions) {
        result = await file(result);
        console.log(result);
     }
})();