wait for function and then console result - node.js

Question

I want to wait for my functions like fetching all result first, then consoling my result.
exports.listofAllFeaturedProd = (req, res) => {
Product.find({is_featured:'1'},function(error,fetchallFeatProds)
{
var allProducts = new Array();
var pp = 0;
var products = new Array();
for (var ProductId in fetchallFeatProds)
{
var pArr = [];
pArr['_id'] = fetchallFeatProds[ProductId]._id;
pArr['name'] = fetchallFeatProds[ProductId].name;
pArr['sku'] = fetchallFeatProds[ProductId].sku;
pArr['description'] = fetchallFeatProds[ProductId].description;
pArr['price'] = fetchallFeatProds[ProductId].price;
pArr['large_image'] = fetchingImage(fetchallFeatProds[ProductId]._id);
pArr['brand'] = fetchingBrand(fetchallFeatProds[ProductId].brand_id);
console.log('#################### IMAGE ####################');
console.log(pArr);
pp++;
}
console.log(products);
});
};
function fetchingImage(pid)
{
ProductImage.findOne({product_id:pid},function(error,fetchallFeatProdsImgs)
{
console.log(fetchallFeatProdsImgs.large_image);
return fetchallFeatProdsImgs.large_image;
});
}
function fetchingBrand(bid)
{
Brand.findOne({_id:bid},function(error,fetchAllBrands)
{
console.log(fetchAllBrands);
return fetchAllBrands;
});
}
node not wait for functions and console undefined after that console my function result. how i stop my code for fetching first result then console all data in array.
Output for console.log(pArr);
[ _id: 57bd996ebf8c930b2bcc06a1,
name: 'New Product',
sku: 'New-Product',
description: 'New Product',
price: 'test',
large_image: undefined,
brand: undefined ]
After that added console inside functions which gave results as below:
Output for fetchingImage
images/12.png
Output for fetchingBrand
{ user_id: '57b42b571fc35e49162de413',
brand_name: '10 Fork ',
brand_logo: 'uploads/brands_logo/1472027911329_5.png',
brand_desc: '10 Fork',
_id: 57bd5ce6cebed2a3189cedcf,
__v: 0 }
Desired output is:
[ _id: 57bd996ebf8c930b2bcc06a1,
name: 'New Product',
sku: 'New-Product',
description: 'New Product',
price: 'test',
large_image: images/12.png,
brand: { user_id: '57b42b571fc35e49162de413',
brand_name: '10 Fork ',
brand_logo: 'uploads/brands_logo/1472027911329_5.png',
brand_desc: '10 Fork',
_id: 57bd5ce6cebed2a3189cedcf,
__v: 0 } ]

Answer 1

Try below code:
var temp = [],
async = require('async');
async.eachSeries(fetchallFeatProds, function(ProductId, callback)
{
pArr['_id'] = ProductId._id;
pArr['name'] = ProductId.name;
pArr['sku'] = ProductId.sku;
pArr['description'] = ProductId.description;
pArr['price'] = ProductId.price;
pArr['large_image'] = fetchingImage(ProductId._id);
pArr['brand'] = fetchingBrand(ProductId.brand_id);
temp.push(pArr);
callback(null);
}, function(err){
console.log(temp); //This should give you desired result
});
If it is not working still, try using callbackfor the functions fetchingImage and fetchingBrand. Or you may try using async.parallel as well inside eachSeries.
EDIT:-
async-eachseries
Change your functions with callback.
function fetchingImage(pid, callback)
{
ProductImage.findOne({product_id:pid},function(error,fetchallFeatProdsImgs)
{
console.log(fetchallFeatProdsImgs.large_image);
callback(error,fetchallFeatProdsImgs.large_image);
});
}
function fetchingBrand(bid, callback)
{
Brand.findOne({_id:bid},function(error,fetchAllBrands)
{
console.log(fetchAllBrands);
calback(error,fetchAllBrands);
});
}
Use async.parallel so that it will wait till both the functions are done. Then push into temp array. Doc to refer
async.eachSeries(fetchallFeatProds, function(ProductId, callback)
{
var pArr = {};
pArr['_id'] = ProductId._id;
pArr['name'] = ProductId.name;
pArr['sku'] = ProductId.sku;
pArr['description'] = ProductId.description;
pArr['price'] = ProductId.price;
async.parallel([
function(callback)
{
fetchingImage(ProductId._id, function(err, res){
pArr['large_image'] = res;
callback(err); //Forgot to add
});
},
function(callback)
{
fetchingBrand(ProductId.brand_id,function(err, res){
pArr['brand'] = res;
callback(err); //Forgot to add
});
},
], function(err){
console.log(pArr); //Edit
temp.push(pArr);
callback(err);
})
}, function(err){
console.log(temp); //This should give you desired result
callback(err);
});