-Template engines (referred to as "view engines" by Express) allow you to specify the structure of an output document in a template
const express = require('express');
const path = require('path');
const app = express();
// Set directory to contain the templates ('views')
app.set('views', path.join(__dirname, 'views'));
// Set view engine to use, in this case 'some_template_engine_name'
app.set('view engine', 'some_template_engine_name');
//Assuming that you have a template file named "index.<template_extension>" that contains placeholders for data variables named 'title' and "message",
//you would call Response.render() in a route handler function to create and send the HTML response:
app.get('/', function(req, res) {
res.render('index', { title: 'About dogs', message: 'Dogs rock!' });
});