The Promise.all() static method takes an iterable of promises as input and returns a single Promise. This returned promise fulfills when all of the input's promises fulfill (including when an empty iterable is passed), with an array of the fulfillment values. It rejects when any of the input's promises rejects, with this first rejection reason.| MDN Web Docs
The map() method of Array instances creates a new array populated with the results of calling a provided function on every element in the calling array.| MDN Web Docs