what is promise.all() code example

Example 1: javascript promise all

var p1 = Promise.resolve(3);
var p2 = 1337;
var p3 = new Promise((resolve, reject) => {
  setTimeout(resolve, 100, "foo");
}); 

Promise.all([p1, p2, p3]).then(values => { 
  console.log(values); // [3, 1337, "foo"] 
});

Example 2: javascript promise.all

// PARALLEL PROMISES
async function fetchMoviesAndCategories() {
  const [moviesResponse, categoriesResponse] = await Promise.all([
    fetch('/movies'),
    fetch('/categories')
  ]);

  const movies = await moviesResponse.json();
  const categories = await categoriesResponse.json();

  return [movies, categories];
}