I don't know why The Output Is Empty Array

let movies = [];
for (let i = 0; i < 40; i++) {
  let apiURL = `https://api.themoviedb.org/3/movie/${i}?api_key=b7e891a7888e6c8135762c0ad4c324c7`;
  fetch(apiURL)
    .then((res) => res.json())
    .then((movie) => {
      movies.push(movie);
    });
}