JSFiddle - React, Tailwind, and code Playground

JavaScript

const promise1 = new Promise(function(resolve, reject) {
  setTimeout(reject, 1500, 'error1');
  setTimeout(resolve, 2000, 'foo');
});
const promise2 = new Promise(function(resolve, reject) {
  setTimeout(reject, 1000, 'error2');
});
const promise3 = Promise.resolve(2*21);


Promise.all([promise1, promise2, promise3]).then(function(values) {
  alert(values);
}).catch((err) => {console.log(err)});