how to get a all count of mongoose model?

Question

how to get a all count of mongoose model?

how can i know the count of a model that data has been saved? there is a method of Model.count(),but it does't work,so please help me,thanks

var db = mongoose.connect('mongodb://localhost/myApp');
var userSchema = new Schema({name:String,password:String});
userModel =db.model('UserList',userSchema);        
var userCount = userModel.count('name');

userCount is a Object,which method called can get a real count?

node.js
mongodb
mongoose

Answer 1

The reason your code doesn't work is because the count function is asynchronous, it doesn't synchronously return a value.

Here's an example of usage:

userModel.count({}, function( err, count){
    console.log( "Number of users:", count );
})

Answer 2

The code below works. Note the use of count.

 var mongoose = require('mongoose');
 var db = mongoose.connect('mongodb://localhost/myApp');
 var userSchema = new mongoose.Schema({name:String,password:String});
 var userModel =db.model('userlists',userSchema);
 var anand = new userModel({ name: 'anand', password: 'abcd'});
 anand.save(function (err, docs) {
   if (err)
       console.log('Error');
   else
       userModel.count({name: 'anand'}, function(err, c)
  {
       console.log('Count is ' + c);
  });
 })

Answer 3

As said before, you code will not work the way it is. A solution to that would be using a callback function, but if you think it would carry you to a 'Callback hell', you can search for "Promisses".

A possible solution using a callback function:

//DECLARE  numberofDocs OUT OF FUNCTIONS
     var  numberofDocs;
     userModel.count({}, setNumberofDocuments); //this search all DOcuments in a Collection

if you want to search the number of documents based on a query, you can do this:

 userModel.count({yourQueryGoesHere}, setNumberofDocuments);

setNumberofDocuments is a separeted function :

var setNumberofDocuments = function(err, count){ 
        if(err) return handleError(err);

        numberofDocs = count;

      };

Now you can get the number of Documents anywhere with a getFunction:

     function getNumberofDocs(){
           return numberofDocs;
        }
 var number = getNumberofDocs();

In addition , you use this asynchronous function inside a synchronous one by using a callback, example:

function calculateNumberOfDoc(someParameter, setNumberofDocuments){

       userModel.count({}, setNumberofDocuments); //this search all DOcuments in a Collection

       setNumberofDocuments(true);


}

Hope it can help others. :)