Correct query using Mongoose, but array is always empty after forEach. Nodejs/MongoDB

I want to return an array of names after a forEach inside an asynchronous method. Both the for each and the res.send are inside the Asyn. Method. The forEach works perfectly, but I always get an empty array.

This is my request in the website side:

function retrieveCharity(){
    $.ajax({
        type:"GET",
        url: "http://xxx.xxx.x.xx:9000/charity",
        success: function(data){
             data.charities.forEach(function(charityName){
                 $(".charity-ul").append("<li>"+charityName+"</li>");
             })
        }
    })
}

This is my router.get listener in the NodeJs side:

router.get('/', function (req, res){
   log.d("Entrou no method post - Charity"); 
   teamModel.find({},function(err,charities){
    var charityMap = {};
        if(err){
            console.log("Err in retrieving Charity")
            log.d("Err in retrieving")
            res.send({
                "status":"error"
            })
        }else{
            charities.forEach(function(charity){
                    charityMap[charity._id]= charity.teamName;
            console.log("Print here the name of the charities I have,PLEASE" + charity.teamName);
                    log.d("foEach - data",charity);
            })
        res.send({
              "charities": charityMap
        })
        }
   })//end of findCahrity

});

All the log.d and the information I ask to be printed inside them is correct, and they are printed. The problem is that the array I return is always empty, but both(forEach) and res.send are inside the asynchronous method.

I always get this in post man:

{
charities: { }
} 

and the console always says :

Uncaught TypeError: undefined is not a function 

this line :

 data.charities.forEach(function(charityName){

Can someone help me please. What am I doing wrong?

Thanks in advance.