如何在promise异步等待方法中循环

Question

我想输出如下：

肯巴利安1:30000肯巴连2:20000肯巴利安3:10000肯巴连4:5000

所以在肯巴连之后，有数字，但我想让它自动

使用此代码

function beliPromise(uang, harga) {
return new Promise(function (resolve, reject) {
setTimeout(function () {
const kembalian = uang - harga;
let angka = i
for (let i = 0; i <= 10; i++) {
console.log(i)
}
console.log(`kembalian ${angka}: ${kembalian}`);
if (kembalian > 0) {
resolve(kembalian);
} else {
reject(0); // atau bisa reject('uang anda habis bro :(')
}
}, 500)
})
}
async function kembalianAwait() {
try {
const kembalian1 = await beliPromise(50000, 20000);
const kembalian2 = await beliPromise(kembalian1, 10000);
const kembalian3 = await beliPromise(kembalian2, 10000);
const kembalian4 = await beliPromise(kembalian3, 5000);
// const kembalian5 = await beliPromise(kembalian4, 50000);
// return kembalian5;
} catch (err) {
throw err
}
}

kembalianAwait()

怎么可能呢？

Answer 1

您可以使用；等待"；在for循环中，例如：

function beliPromise(uang, harga) {
return new Promise(function (resolve, reject) {
setTimeout(function () {
const kembalian = uang - harga;
if (kembalian >= 0) {
resolve(kembalian);
} else {
reject();
}
}, 500)
})
}
let uang = 50000;
async function kembalianAwait() {
const harga = [20000, 10000, 10000, 5000];
try {
for (let i = 0; i < harga.length; i++) {
let kembalian = await beliPromise(uang, harga[i])
console.log(`kembalian ${i + 1}: ${kembalian}`);
uang = kembalian
}
} catch (err) {
console.log(err);
}
}

注意>=0的用法，我认为有确切的金额不应该导致错误。

Answer 2

使用全局索引变量：

var index  = 1
function beliPromise(uang, harga) {
return new Promise(function(resolve, reject) {
const kembalian = uang - harga;
console.log(`kembalian ${index}: ${kembalian}`);
index ++;
if (kembalian > 0) {
resolve(kembalian);
} else {
reject(0); // atau bisa reject('uang anda habis bro :(')
}

})
}
async function kembalianAwait() {
try {
const kembalian1 = await beliPromise(50000, 20000);
const kembalian2 = await beliPromise(kembalian1, 10000);
const kembalian3 = await beliPromise(kembalian2, 10000);
const kembalian4 = await beliPromise(kembalian3, 5000);
// const kembalian5 = await beliPromise(kembalian4, 50000);
// return kembalian5;
} catch (err) {
throw err
}
}
kembalianAwait()

Answer 3

您有一个循环，但引用了循环外的i。您需要将循环的代码包含到循环中：

function beliPromise(uang, harga) {
return new Promise(function (resolve, reject) {
setTimeout(function () {
const kembalian = uang - harga;
for (let i = 0; i <= 10; i++) {
let angka = i
console.log(i)
console.log(`kembalian ${angka}: ${kembalian}`);
if (kembalian > 0) {
resolve(kembalian);
} else {
reject(0); // atau bisa reject('uang anda habis bro :(')
}
}
}, 500)
})
}
async function kembalianAwait() {
try {
const kembalian1 = await beliPromise(50000, 20000);
const kembalian2 = await beliPromise(kembalian1, 10000);
const kembalian3 = await beliPromise(kembalian2, 10000);
const kembalian4 = await beliPromise(kembalian3, 5000);
// const kembalian5 = await beliPromise(kembalian4, 50000);
// return kembalian5;
} catch (err) {
throw err
}
}

kembalianAwait()