EJS (Embedded JavaScript or perhaps Effective or Elegant or Easy JavaScript) is a templating language that lets you generate HTML markup using JavaScript. EJS enables server-side rendering of HTML and is available as a Node module, making it a popular choice for managing templates in server-side environments.

Setup

Setting up a Node.js application with EJS requires these steps:

• Installing EJS (via NPM)

npm i ejs

• Adding the following startup code (code shown below on the index.js file of an Express-based Node application)

const express = require('express');
const app = express();
const path = require('path')

app.set('view engine', 'ejs')
app.set('views', path.join(__dirname, 'views')) // Specifies where EJS templates are located relative to index.js

Rendering EJS

From an Express-based Node application, rendering an EJS template is as easy as the following line of code

app.get('/=', (req, res) => {    
	res.render('index', {user: userDetails})  
})

This code looks for an index.ejs file in the views directory and renders it on screen. The index.ejs template also receives a user object (passed as the second parameter).

Passing Variable to a Partial

To pass a variable from an EJS template to a partial, you can either pass the variable as-is or use a template string with string interpolation, as shown below

<%- include('partials/header', {title: user }) %> // Passing incoming variable as-is
<%- include('partials/header', {title: `User Details - ${user.name}` }) %> // Templated string