If you have used any social media app like Facebook or Instagram, you might have noticed that the layout of my user profile is the same to yours. Very often, different pages within the same website have the same layout, just slightly different content.

e.g. Different youtube videos have different number of views and stuff, but the same layout.

Templating is when you define a preset layout for a webpage, that we can dynamically modify its content on-the-fly.

There are many templating engines or templating languages we can use to make dynamic webpages, some examples are handlebars, jade, pug, nunjucks, and the one I will be covering in this guide is EJS, which stands for Embedded JavaScript.

EJS link

Note: Before you proceed reading you need to know how Express Servers work, where you can checkout my Express Guide

EJS is "advanced html".

First install ejs using npm:

npm i ejs

To incorporate EJS with an Express App, you have to include the line:

app.set("view engine", "ejs");

By default, for any express app, when we use a view engine then the app will assume the templates will exist in the views directory.

As best practice, to be able to invoke app from any directory and for the app being able to find the views folder from its directory and not cwd, you should specify the path:

const path = require("path");
app.set("views", path.join(__dirname, "/views"));

After you specify this path, you should be able to run app from any directory and not get a Failed to lookup view <ejs> in views directory error.

• <%= Output value
• ``

Templates should have as little logic as possible. Templates should be stupid, they should only display.

To pass things to templates, you can use the res.render function:

app.get('/rand', (req, res) => {
    const num = Math.floor(Math.random() * 10) + 1;
    res.render("random", { rand: num });
})

Here, I am passing a JS Object as parameter to ejs.