MongoDb 节点 js .then .fail

Question

我如何编写代码来做同样的事情，但使用 .then 和 .fail

在下面的代码中，第 1 行的 db.get() 将连接返回为 db.collection('......).find({}) 中的“db”。换句话说 db.get() 与 db 是一样的；我在一个单独的模块中连接到 mongodb。

db.get().collection('type').findOne({"_id":objId}, function(err, typeInfoResult){
    try{
        if(err){
            res.send(errMsg);
        } 
        else{
            var business_id = typeInfoResult.business_id;
            db.get().collection('business_info').findOne({"_id":ObjectID(business_id)}, function(err, businessInfoQuery){
                if(err){
                    res.send(errMsg);
                }
                else{
                    var completetypeDetail = {typeDetails:typeInfoResult, BusinessDetails:businessInfoQuery};
                    res.send(completetypeDetail);
                }
            })
        }
    }catch(err){
        res.send(errMsg); 
        }
    });
});

Answer 1

在下面试试这个：

db.collection('type').find({"_id":objId}).toArray(function(err, typeInfoResult){
try{
    if(err){
        res.send(errMsg);
    } 
    else{
        var business_id = typeInfoResult.business_id;
        db.get().collection('business_info').findOne({"_id":ObjectID(business_id)}, function(err, businessInfoQuery){
            if(err){
                res.send(errMsg);
            }
            else{
                var completetypeDetail = {typeDetails:typeInfoResult, BusinessDetails:businessInfoQuery};
                res.send(completetypeDetail);
            }
        })
    }
}catch(err){
    res.send(errMsg); 
    }
});

Answer 2

这是一个例子，因为我前几天刚刚连接了 MongoDB：

./config/mongodb.js

 // Load MongoDB Driver
 const MongoClient = require('mongodb').MongoClient;

 /**
  *
  * Instantiate MongoDB Connection
  *
  * Additional options:
  * https://docs.mongodb.com/manual/reference/connection-string/#connection-string-options
  */

 // Connect database
 export const MongoDB = new Promise((resolve, reject) => {
   // MongoDB Connection Info
   let url = `mongodb://${Singleton.currentConfig.databases.mongodb.user}:`;
   url += `${Singleton.currentConfig.databases.mongodb.password}@`;
   url += `${Singleton.currentConfig.databases.mongodb.host}:`;
   url += `${Singleton.currentConfig.databases.mongodb.port}/?authMechanism=DEFAULT&`;
   url += `authSource=${Singleton.currentConfig.databases.mongodb.db}`;

   // Use Connect Method to connect to the Server
   MongoClient.connect(url)

     .then((db) => {
       console.log('Casually connected correctly to server.');
       resolve(db);
     })

     .catch((error) => {
       console.log(`MongoDB Connection Error: ${error}`);
       reject(error);
       process.exit(0);
     });
 });

./app.js

 const MongoDB = require('./config/mongodb');
 // or
 // import MongoDB from './config/mongodb';

 // Acquire an object
 userDetails = { email: 'async@await.com', firstName: 'Uwot', lastName: 'Mate' };

 // Create a user
 MongoDB.collection('users').insertOne(userDetails)

   .then((done) => {
     console.log(`Added: ${done}`);
   })

   .catch((error) => {
     throw new Error(`Fecal's on fire, yo: ${error}`);
   });