我有一个异步函数，它遍历一个数组，对每个元素进行另一个异步调用，等待结果。
public async myfetch(parent_id: string): Promise<Record[]> {
let payload = await this.load(parent_id);
let records = [];
await payload.items.forEach(async (item: any) => {
let child = await this.load_another_api(item.child_id);
let record = {
a: child.a,
b: child.b,
}
records.push(record)
}
return records;
}而负载的签名，load_another_api 就像：
public async load(Id: string): Promise<any> {
/// some logic to build requestUrl
return fetch(requestUrl, options)
.then((response) => { return response.json(); });
}但是当我调试时，我看到 myfetch 函数在调用所有 for 循环项之前返回到调用者 load_another_api 并等待结果并填充到 records 数组。
你能告诉我我错过了什么吗？
回答1
您可以改用 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map 和 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all 来执行此操作。像这样的东西：
public async myfetch(parent_id: string): Promise<Record[]> {
const payload = await this.load(parent_id);
const promises = payload.items.map((item: any) =>
this.load_another_api(item.child_id)
.then((child: any) => ({a: child.a, b: child.b})));
return Promise.all(promises);
}