javascript - 如何将回调 hell 重写为 promise ？

Question

我的回调 hell 路线工作正常...

var myCallbackHell = router.route('/');
myCallbackHell.get(function(req, res, next) {
  bookModel.find({title: "Animal Farm"}).then(function(book) {
    movieModel.find({title: "Intouchables"}).then(function(movie) {
      gameModel.find({title: "The Last of Us"}).then(function(game) {
        res.render('index', {book_found: book, movie_found: movie, game_found: game});
      });
    });
  });
});

但是我想使用 promise。任何帮助，提示？

Answer 1

您可以使用 Promise.all并像这样写一样

var promises = [
  bookModel.find({title: "Animal Farm"}),
  movieModel.find({title: "Intouchables"}),
  gameModel.find({title: "The Last of Us"})
];

Promise.all(promises).then(function(values) {
  res.render('index', {book_found: values[0], movie_found: values[1], game_found: values[2]});
}).catch(function(err) {
  // deal with err
});