Pass variable from JavaScript to pug

Question

I'm experimenting with Node.js and MongoDB using an Express scaffold.

I am trying to achieve the following:

1. Connect to MongoDB and pull a document out of a collection (this I have managed to do).
2. Display the returned document as html (this is the bit I need help with).

My index.js file looks like this:

var express = require('express');
var router = express.Router();
var MongoClient = require('mongodb').MongoClient, assert = require('assert');

/* GET home page. */
router.get('/', function(req, res, next) {
    MongoClient.connect('mongodb://localhost:27017/beetleJuice', function (err, db) {

        assert.equal(null, err);

        // assign the bugs collection to var col
        var col = db.collection('bugs');

        col.findOne({"assignee" : "John Smith"}, function (err, doc) {

            assert.equal(null, err);

            // Print the resulting document to the console
            console.log("Here is my doc: %j", doc);

            // Close the connection to the database
            db.close();
        }); 
    });

    res.render('index'); // How do I pass the doc over to index.jade?
});

module.exports = router;

My assumption was that I could pass the doc variable by doing something like:

res.render('index', doc); 

However, when I try this I get an error saying that doc is not defined.

Any suggestions on what I'm doing wrong here?

Answer 1

Thanks to the comment from felix the solution is to move the res.render inside the callback of the findOne function:

    col.findOne({"assignee" : "John Smith"}, function (err, doc) {

        assert.equal(null, err);

        // Print the resulting document to the console
        console.log("Here is my doc: %j", doc);

        res.render('index', doc);

        // Close the connection to the database
        db.close();

    }); 
});