Is EJS the Secret Weapon for Dynamic Web Pages?

Crafting Dynamic HTML: The Magic of EJS Templating for Web Developers

Jul 8, 2024

Is EJS the Secret Weapon for Dynamic Web Pages?

Mastering EJS: Your Go-To Templating Language for Dynamic Web Content

In the ever-evolving world of web development, templating engines play a significant role in generating dynamic HTML content. EJS—short for Embedded JavaScript—is one of those tools that stands out because of its simplicity and effectiveness. If you’re looking to create dynamic web pages using plain JavaScript, EJS offers a smooth and straightforward way to do it.

What Exactly is EJS?

EJS is essentially a templating engine that lets you embed JavaScript directly into your HTML templates. What makes EJS cool is that you don’t need to learn any new syntax. You get to use the JavaScript you already know and love. It’s all about keeping things simple and intuitive, making your life a lot easier when you’re working on web development projects.

Getting Started with EJS

Before you can dive into using EJS, you’ll need to install it via npm (Node Package Manager). It’s a breeze to set up. Just hop into your terminal and run:

npm install ejs

Once it’s installed, you can set up EJS as your templating engine, especially if you’re working with Node.js frameworks like Express.

Basic Usage: The Fun Begins

Working with EJS involves passing a template string and some data to the ejs.render method. Here’s a straightforward example to get your gears turning:

let ejs = require('ejs');
let people = ['geddy', 'neil', 'alex'];
let html = ejs.render('<%= people.join(", "); %>', { people: people });
console.log(html); // Output: "geddy, neil, alex"

In this snippet, the template string <%= people.join(", "); %> contains a JavaScript expression that EJS evaluates when rendering the HTML.

Integrating EJS into HTML Templates

EJS really shines when you start embedding it directly into HTML files to generate dynamic content. Imagine you have a file called home.ejs with this content:

<!DOCTYPE html>
<html>
<head>
    <title>Home Page</title>
</head>
<body>
    <h1>Welcome, <%= name %></h1>
</body>
</html>

To render this template in your Node.js app using Express, you’d set things up like this:

const express = require('express');
const app = express();
app.set('view engine', 'ejs');

app.get('/', (req, res) => {
    res.render('home', { name: 'Akashdeep' });
});

app.listen(4000, () => {
    console.log('Listening to port 4000');
});

When someone visits the root URL, the home.ejs template renders with “Akashdeep” embedded into the HTML.

Getting to Know EJS Template Tags

EJS utilizes several template tags to control the flow and output of your templates. Here’s a quick rundown of the key tags:

<%= %>: Outputs the value of a variable. For instance, <%= name %> will print the value of the name variable.
<%- %>: Similar to <%= %>, but it doesn’t escape HTML. Be careful with this one to avoid XSS vulnerabilities.
<% %>: Great for control-flow statements like if-else and loops. For example:
```
<% if (user) { %>
    <h2><%= user.name %></h2>
<% } %>
```
<%# %>: Used for comments. Anything inside this tag won’t be rendered in the final HTML.

Breaking Down Templates with Includes and Partials

Modularity is key when managing large codebases. EJS supports includes, allowing you to break down templates into smaller, reusable components. Here’s a simple example:

<%- include('header'); -%>
<h1>My Page</h1>
<p>This is my page content.</p>
<%- include('footer'); -%>

In this example setup, header.ejs and footer.ejs are included in the main template, making the HTML structure easier to manage.

Speeding Things Up with Caching

Caching can drastically improve performance. EJS provides caching features, which you can set up using the LRU (Least Recently Used) cache module:

let ejs = require('ejs');
let LRU = require('lru-cache');
ejs.cache = LRU(100); // Cache up to 100 items

This setup ensures that frequently used templates are cached, reducing the rendering overhead.

Going Custom with File Loaders

Sometimes you need extra control over how EJS loads its templates. You can define a custom file loader to fit your specific needs. Here’s an example:

let ejs = require('ejs');
let fs = require('fs');

let myFileLoader = function (filePath) {
    return 'myFileLoader: ' + fs.readFileSync(filePath, 'utf8');
};

ejs.fileLoader = myFileLoader;

Custom loaders can be handy, especially if you need to preprocess files before rendering them.

EJS in the Browser: Why Not?

EJS isn’t just for server-side rendering; you can use it directly in the browser as well. Just include the EJS library via a script tag and render templates on the client side:

<script src="ejs.min.js"></script>
<script>
    let people = ['geddy', 'neil', 'alex'];
    let html = ejs.render('<%= people.join(", "); %>', { people: people });
    document.getElementById('output').innerHTML = html;
</script>
<div id="output"></div>

This can be useful for quick and simple templating tasks without needing a server setup.

Stay Safe: Security Considerations

Security is a crucial aspect of web development. When using EJS, especially when dealing with user input, make sure the inputs are properly sanitized. Avoid passing untrusted data directly to the ejs.render method to prevent code injection attacks.

Wrapping Up: EJS is a Win

All in all, EJS is a fantastic and straightforward templating language that leverages the familiarity of JavaScript to help you generate dynamic HTML content. Its user-friendly approach, flexibility, and performance make it a favorite among web developers. Whether you’re building a complex web application or just need a quick way to template some HTML, EJS is definitely worth a look. With its sturdy feature set and active community support, EJS remains a top choice in the web development toolkit.