Passing mongodb data into views through express - node.js

Question

I am building a VERY basic application to book a vehicle for hire, I am trying to access data from mongodb, which seems to work, as it outputs to the console on load. I cannot get this information to render in my view. If I set the render method outside of the function scope I cannot access the db data, if I set the render inside then the booking page never loads. I have been messing around with the same block of code for days now and I have had no joy.
//------------------------------------------------THE SET UP--------------------------------------------
// set node dependencies
let express = require("express");
let bodyParser = require("body-parser");
let mongoose = require("mongoose");
let connection = mongoose.connection;
let data = mongoose.connect("mongodb://localhost:27017/test")
// allow for encoding od POST DATA
let urlencodedParser = bodyParser.urlencoded({extended: false});
// set up app to extend express
let app = express();
// view engine
app.set("view engine", "ejs");
// static files
app.use("/assets", express.static("assets"));
//------------------------------------------------------------------------------------------------------
// REDIRECTS BASED ON URL
app.get('/', function(req,res){
res.render("index")
});
app.get('/booking', function(req,res){
res.render("booking",{qs:req.query})
});
app.post('/booking',urlencodedParser, function(req,res){
// Surround this with if !blacklisted to run inner code
if (req.body.blacklist !== "on"){
console.log(req.body);
// booking page takes age details and redirects/queries database accordingly
if (req.body.age >= 25){
connection.once('open', function () {
connection.db.collection("vehicles", function(err, collection){
collection.find({}).toArray(function(err, data){
console.log(data[0]._id); // it will print collection data
})
});
res.render("contact-success",{data:req.body})
connection.close();
});
}
else if (req.body.age < 25 && req.body.age > 17){
connection.once('open', function () {
connection.db.collection("vehicles", function(err, collection){
collection.find({}).toArray(function(err, data){
console.log(data[0]._id + "<25 message"); // it will print collection data
})
})
})
// THIS IS WHERE I WANT TO PASS THE DB DATA INTO.. so that it redirects to this page and filters the vehicles collection appropriately.
res.render("contact-failed",{data:req.body});
}
}
else{
console.log(req.body.firstName , req.body.lastName , "Has been blacklisted!")
res.render("blacklisted",{data:req.body});
}
// else if blacklisted redirect to a sorry, contact company page.
});
let port = 3000;
app.listen(port);
console.log("listening on port " + port);

Answer 1

Few things about your code -
You should call res.render() inside the call to mongodb.
connection.once('open', function () {
connection.db.collection("vehicles", function(err, collection){
collection.find({}).toArray(function(err, data){
console.log(data[0]._id); // it will print collection data
res.render("contact-success",{data:req.body})
});
});
connection.close();
});
You are not checking for errors. If you get any error with query, you will end up with no response to the request. So it's always better to check for errors.
if(err) {
// process the error and send appropriate message.
} else {
// send what you want to send to view.
res.render("contact-success",{data:req.body})
}
You have conditions for
if (req.body.age >= 25){
...
} else if (req.body.age < 25 && req.body.age > 17){
...
}
But there is nothing for plain else. So if any of the two conditions is not met, you will end up with no response to the request.
There should be one res.render() or res.send() in each of the conditions.