如何等待Mongoose搜索的返回？

Question

我用NodeJS / Mongoose创建了一个CRUD，以MVC风格分割文件。在路由示例中，我将在下面显示，当执行retrieveOne例程时，必须等待其处理，然后将用户重定向到一个或另一个路径。我想用Bluebird等待处理。我需要一些帮助来实现例程。

Index.js -----------------------------------------------

const myCRUD = require('./api/controllers/controller')

router.post('/login', function(req, res, next) {   

   // HOW TO IMPLEMENT BLUEBIRD HERE?

   // How to wait for the "retrieveOne" process and a then do a "if" test (below)?   
   let ret = myCRUD.retrieveOne({ name: "abc test" }); 


   if(!ret) {
      res.redirect('/success')
   } else {
      res.redirect('/error')
   }
})

controller.js ------------------------------------------

const mongoose = require('mongoose');
const Schema = require('./schema-user');
const Model = mongoose.model('users', Schema);

const CRUD = {
   retrieveOne: function(query) {
      Model.findOne(query, function(err, result) {
         if (err) return err;
         return result;
      });
   }
}

module.exports = CRUD;

注意：我已经在S.O.中找到了几个有和没有Bluebird的例子，但我无法让它起作用：例子：1，2，3，4，5

Answer 1

使用async和await

const myCRUD = require('./api/controllers/controller')
const Promise = require('bluebird');

router.post('/login', async function(req, res, next) {   

   // HOW TO IMPLEMENT BLUEBIRD HERE?

   // How to wait for the "retrieveOne" process and a then do a "if" test (below)?   
   let ret = await myCRUD.retrieveOne('{ name: "abc test"'); 


   if(!ret) {
      res.redirect('/success')
   } else {
      res.redirect('/error')
   }
})

// controller.js ------------------------------------------

const mongoose = require('mongoose');
const Schema = require('./schema-user');
const Model = mongoose.model('users', Schema);

const CRUD = {
   retrieveOne: function(query) {
      return new Promise((resolve, reject) => {
        Model.findOne(query, function(err, result) {
           if (err) reject(err);
           resolve(result);
        });
      });
   }
}

module.exports = CRUD;

Answer 2

你真的不需要使用Bluebird，因为mongoose可以很好地使用本机Promises

在你的控制器中：

const mongoose = require('mongoose');
const Schema = require('./schema-user');
const Model = mongoose.model('users', Schema);

const CRUD = {
   retrieveOne: function(query) {
      // findOne() returns a Promise ()
      // https://mongoosejs.com/docs/promises.html
      return Model.findOne(query);
   }
}

module.exports = CRUD;

现在，您可以使您的路由处理程序成为async函数，并且只需将await作为Promise

const myCRUD = require('./api/controllers/controller')

router.post('/login', async function(req, res, next) { 
   let ret = await myCRUD.retrieveOne({ name: "abc test"}); 
   if(!ret) {
      res.redirect('/success')
   } else {
      res.redirect('/error')
   }
})