如何使用猫鼬 Promise - mongo [英] How to use mongoose Promise - mongo

问题描述

谁能给我举个例子，说明如何在猫鼬中使用 Promise.这是我所拥有的，但它没有按预期工作:

Can someone give me an example on how to use a Promise with mongoose. Here is what I have, but its not working as expected:

app.use(function (req, res, next) {
  res.local('myStuff', myLib.process(req.path, something));
  console.log(res.local('myStuff'));
  next();
});

然后在 myLib 中，我会有这样的东西:

and then in myLib, I would have something like this:

exports.process = function ( r, callback ) {
  var promise = new mongoose.Promise;
  if(callback) promise.addBack(callback);

  Content.find( {route : r }, function (err, docs) {
     promise.resolve.bind(promise)(err, docs);

  });

  return promise;

};

在某些时候，我希望我的数据会出现，但我该如何访问或获取它?

At some point I am expecting my data to be present, but how can I access it, or get at it?

推荐答案

在当前版本的 Mongoose 中，exec() 方法返回一个 Promise，因此您可以执行以下操作:

In the current version of Mongoose, the exec() method returns a Promise, so you can do the following:

exports.process = function(r) {
    return Content.find({route: r}).exec();
}

然后，当你想要获取数据时，你应该让它异步:

Then, when you would like to get the data, you should make it async:

app.use(function(req, res, next) {
     res.local('myStuff', myLib.process(req.path));
     res.local('myStuff')
         .then(function(doc) {  // <- this is the Promise interface.
             console.log(doc);
             next();
         }, function(err) {
             // handle error here.
         });
});

关于 Promise 的更多信息，我最近阅读了一篇精彩的文章:http://spion.github.io/posts/why-i-am-切换到promises.html

For more information about promises, there's a wonderful article that I recently read: http://spion.github.io/posts/why-i-am-switching-to-promises.html

这篇关于如何使用猫鼬 Promise - mongo的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！