Example of usage Promise.race

Promise.race.js

var getPromise = (value, delay) => {
  return new Promise(resolve => {
    setTimeout(() => resolve(value), delay);
  });
};

var promise1 = getPromise('value-1', 350);
var promise2 = getPromise('value-2', 250);
var promise3 = getPromise('value-3', 150);

var promise = Promise.race([promise1, promise2, promise3]);
promise
.then(result => {  
  console.log('result of promise:', result); 
})
.catch(error => {
  console.log('error', error);
});
// Will be printed 'result of promise: value-3' after small delay

I am not sure that it’s a real usage example. I suppose that race could be applied to show any deffered interaction on the UI or make request calls with some back-up functionality. For instance, we have the multiple API requests to some health/check endpoints and want return first-done value.

@captainkovalsky: https://stackoverflow.com/a/48756791/118153