How to make sure async functions work seriesly in TypeScript

Question

Given

const list = [1,2,3,4,5,6,7];
let results = [];

and a function

powerNumPlusOne = async(num) : Promise<any> => {
     return powerNum*powerNum + 1;
}

how to make sure this code work

list.forEach(async function(i){
   results.push( await this.powerNumPlusOne(i));
})

and the results should be [2,5,10,17,26,37,50] in order?

Your function does nothing asynchronous. Just make it synchronous, don't return a promise, and you won't have any problems. (Btw this is also the reason why your example already does output the expected result) — Bergi, Nov 22 '19 at 01:28
https://caolan.github.io/async/v3/index.html `const _async = require('async'); let results = []; let tasks = []; list.forEach((i) => { tasks.push((callback) => { this.powerNumPlusOne(i).then( (res) => { results.push(res); callback(null, res); } ); }) }) _async.series(tasks, (err, res) => { console.log(res); })` — Jerry, Nov 22 '19 at 04:03
No, if you want to work with promises, don't use the `async.js` library for callback-style. — Bergi, Nov 22 '19 at 08:54

score -1 · Answer 1 · answered Nov 22 '19 at 01:30

You could use Promise.all(). It accepts an number of actions and returns them in exactly the same order when all complete.

const list = [1,2,3,4,5,6,7];
let actions = list.map(powerNumPlusOne);
let results = await Promise.all(actions);
enter code here

1 Answers1