for loop giving an error while inserting document to collection - node.js

Question

In node.js I am writing query to insert document to collection, but that query inserting only one document. Below the js code is,
app.js
router.post('/creatList', function(req,res){
console.log(req.body.email);
var emails = req.body.email;
if(req.body.wData.wishListType == 'Shared'){
var findUsers = function(db, callback) {
var cursor;
cursor = db.collection('users').find({email: { $in: emails }})
cursor.toArray(function(err, docs){
if(err){
callback(new Error("Some problem"));
} else {
callback(null,docs);
}
});
};
MongoClient.connect(config.database, function(err, db) {
assert.equal(null, err);
findUsers(db, function(err,docs) {
db.close();
console.log(docs);
var inserts_processing = 0;
for(var key in docs){
console.log(key);
var ids = docs[key]._id;
inserts_processing++;
console.log(ids);
var insertDocument = function(db, callback) {
db.collection('notifications').insertOne({
"userId" : ids,
},function(err, result) {
inserts_processing--;
assert.equal(err, null);
console.log("Inserted a document into the notifications collection.");
if(inserts_processing == 0){
db.close();
callback();
}
});
};
MongoClient.connect(config.database, function(err, db) {
assert.equal(null, err);
insertDocument(db, function() {
db.close();
});
});
}
});
});
} else {
console.log("other");
}
});
In the above code console.log contains two ids 570dec75cf30bf4c09679deb
56fe44836ce2226431f5388f but actually it inserting only last one.

Answer 1

According to your updated code I will try the following
router.post('/creatList', function(req,res){
console.log(req.body.email);
var emails = req.body.email;
if(req.body.wData.wishListType == 'Shared'){
// Open one connection to find users and insert documents
MongoClient.connect(config.database, function(err, db) {
assert.equal(null, err);
if(!err){
findUsers(db, function(err,docs) {
if(!err){
insertDocs(db, docs, function(){
db.close(); // Close connection
console.log("All documents have been inserted");
res.status(200).send("All is OK");
});
}
});
});
}
} else
console.log("other");
});
function insertDocs(db, docs, callback){
var inserts_processing = 0; // Will contain the number of inserts pending operation
for(var key in docs){
var ids = docs[key]._id;
inserts_processing++; // Before writing data, add one to processing inserts
db.collection('notifications').insertOne({
"userId" : ids,
}, function(err, result) {
inserts_processing--; // One insert have been finished, so remove one
assert.equal(err, null);
console.log("Document inserted into the notifications collection.");
// If all inserts have been finished, call back the function
if(inserts_processing == 0)
callback();
});
}
}
function findUsers(db, callback) {
var cursor;
cursor = db.collection('users').find({email: { $in: emails }})
cursor.toArray(function(err, docs){
if(err)
callback(new Error("Some problem"));
else
callback(null,docs);
});
};