example.js

exports.getMovieFromId = function(id) {
  return table_movies.select('*').where({ movie_id: id }).first().then((movie) =>
    if (movie) return movie
    return movies.insert(...).returning('*')  // returns promise that resolves as the inserted movie
  });
};

exports.getMovies = function() {
  return Promise.all([
      exports.getMovieFromId(1),
      exports.getMovieFromId(2),
      exports.getMovieFromId(3),
      exports.getMovieFromId(4),
      exports.getMovieFromId(5),
  ])
};