the variable i is not filled - node.js

Question

I have declare the variable first. but if I do console.log(userinsertData) outside looping variable still not fill.
what i should do for solving this problem?
here my code:
var User = require('../models/user');
module.exports = {
myaction: function(req, res, next) {
var data = req.body,
userinsertData = [];
try {
data.forEach(function(item, index) {
var userdata = new User();
userdata.name = item.name;
userdata.age = item.age;
userdata.sex = item.sex;
userdata.save(function(err, data) {
if (err) {
res.send(err)
} else {
userinsertData.push(data);
}
});
})
} catch (e) {
res.json({
message: 'data not valid'
})
}
console.log(userinsertData);
res.json({
message: 'musician created!',
data: userinsertData
});
}
};

Answer 1

you should solve the problem as
async.eachSeries(data, function (info, callback) {
//here process your data and call callback() for next iteration
}, function (err) {
if (err) {
//this will be called after all iterations and in case of error
}else{
console.log('Well done :-!');
//this will be called after all interations successfully
}
});
this problem you are facing is because of asynchronous nature of nodejs and async helps you to introduce blocking.
Don't forget to include async

Answer 2

Use promise
var User = require('../models/user');
module.exports = {
myaction: function(req, res, next) {
var data = req.body,
userinsertData = [];
new Promise(function(resolve, reject) {
data.forEach(function(item, index) {
var userData = new User(item);
userData.save(function(err, data) {
// if error, reject
if(err) return reject(err);
// we have proceed all items in data, resolve it
else if(data.length - 1 === index) return resolve(userinsertData);
// not finished yet, keep proceeding
else userinsertData.push(data);
});
}).then(function(successResult) {
res.json({
message: 'musician created!',
data: successResult
});
}, function(errorResult) {
res.json({
message: 'data not valid'
});
});
}
};
Use callbacks
var User = require('../models/user');
module.exports = {
myaction: function(req, res, next) {
var data = req.body,
userinsertData = [];
function saveUser(callback) {
data.forEach(function(item, index) {
var userData = new User(item);
userData.save(function(err, data) {
// if error, return callback with error
if(err) return callback(err);
// we have proceed all items in data, return data
else if(data.length - 1 === index) callback(null, userinsertData);
// not finished yet, keep proceeding
else userinsertData.push(data);
});
}
saveUser(function(err, users) {
if(err) return res.json({message: 'data not valid'});
res.json({
message: 'musician created!',
data: users
});
});
}
};
This is what async package does internally