ES6 Promise.all progress

Question

I’ve knocked up a little helper function that you can re-use.

Basically pass your promises as normal, and provide a callback to do what you want with the progress..

function allProgress(proms, progress_cb) {
  let d = 0;
  progress_cb(0);
  for (const p of proms) {
    p.then(()=> {    
      d ++;
      progress_cb( (d * 100) / proms.length );
    });
  }
  return Promise.all(proms);
}

function test(ms) {
  return new Promise((resolve) => {
    setTimeout(() => {
       console.log(`Waited ${ms}`);
       resolve();
     }, ms);
  });
}


allProgress([test(1000), test(3000), test(2000), test(3500)],
  (p) => {
     console.log(`% Done = ${p.toFixed(2)}`);
});

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