While loops using Await Async.

Question

This Javascript function seems to use the while loop in an asynchronous way. Is it the correct way to use while loops with asynchronous conditions?

 var Boo         


        

Answer 1

Its been awhile since this question was asked. I am new to js after many years of other languages (starting with punch cards and paper tape) and needed to solve this problem. Here is my answer:

var loopContinue = true;
var n = 0;

async function  Managework() {
  while (loopContinue) {  //seemingly an infinite loop
    //await (doWork(n));
    await (doWork(n).catch(() => { loopContinue=false; }));
    n++;
    console.log(`loop counter ${n}`);
  }
  console.log(`loop exit n=${n} loopContinue=${loopContinue}`);
 }

Managework();

function doWork(n) {
 return new Promise((resolve, reject) => {
    console.log(`dowork(${n})`);
    if (n > 5) {
      //loopContinue = false;
      reject(`done`);
    }
    setTimeout(() => {
      resolve('ok');
    }, 1000);
  });
}

As desired the loop breaks after the 5th iteration. 'loopContinue' global can either be set in the work function or in the catch (or could be the then) of the promise. I tired just using 'break' in the then or catch but I get an error.

If you want to do it in doWork you can eliminate the catch and and just call doWork() and uncomment the // loopContinue= false in doWork. Either way works. This was tested with node.js

I found stuff on nextTick but this seems much easier.