Update Object and push to Array using async and await function?

Question

We are using async and await to collect the count from another function but getting Promise Issues, We know to use then() but need to update outer array/object.

How can we wait still update forEach element and push to the array?

sample code :

module.exports = {
    getQuestionCounts: function(req, res){ // connected with Routes
        var arr = [];
        req.data.forEach(element => {
            module.exports.getCounts(element).then(function(count){
                console.log(count); // getting value
                element.count = count; 
                arr.push(element); // not updating with array
            });                  
        });           
        if(arr.length > 0){ // other operations }
    }
    getCounts: async function(data){
        var count = await Questions.countDocuments({"object":{$elemMatch: {data}}}).then(function(result){
            return result;
        });
        console.log(count); // getting count Fine
        return count;
    }
}

Answer 1

getCounts returns a Promise so you can use .then callback or async/await

getQuestionCounts: function(req, res){
  var arr = [];
  // not sure why you're doing this way
  module.exports.getCounts(req.data).then(data => {
    // data is available only here
    console.log(data);
    arr.push(data)
    // use arr here
  })
  // arr will be empty
  console.log(arr)
}

async/await

getQuestionCounts: async function(req, res){
  try {
    var arr = [];
    var count = await module.exports.getCounts(req.data);
    arr.push(count);
  } catch (e) {
    //handle error
    console.error(e)
  }
}

Note: All async function returns Promise

Preferable way to use module.exports

function someFunc() {
  return something;
}

function anotherFunc() {
  const result = someFunc()
  // do something
  return another;
}

module.exports = {
  // if you still want to export someFunc
  someFunc
  anotherFunc
}