使用异步迭代来链接承诺

Question

I have an array of items ( projects ) I want to upload, one by one in sequence.

I know how to do this by constructing a promise chain, but I wanted to try and use an async iterator and for...await .

First I map the projects to arrow functions which will, when called, invoke the upload; then I create an async iterable via an async generator function.

Then I use for...await to loop over the async iterable.

Is this an idiomatic approach?

For example, (p)=>()=>upload(p) looks strange to me, as does the IIFE (async function*() { for (let p of arr) yield p() }()) .

 const upload = ({name}) => new Promise((resolve) => setTimeout(() => resolve(`Response for upload of: ${name}`), 1000)) const asyncIter = (arr) => (async function*() { for (let i of arr) yield i() }()) const uploadInSeries = async (arr) => { const iter = asyncIter(arr.map((i) => () => upload(i))) for await(let response of iter) { console.log(response) } } const projects = [{ name: "P1" }, { name: "P2" }, { name: "P3" }] uploadInSeries(projects)

Answer 1

This is not a usecase for an async iterable. Async iterables only make sense if you don't know wether you have a next element or not. In your case however, the number of requests is already known, so you can just do

 for(const el of arr)
   await request(el);