Hello Everyone! I am here today with one of the interesting topics, Handlebars!
What are Handlebars
Handlebars is a lightweight, templating engine used to generate HTML dynamically by combining templates with data.
Okay, if in that case, what is templating or template here!?
A template is a reusable pattern with blanks that get filled with actual data to produce a finished or completed/whole document or page. Here we can have JSON as actual data.
Handlebars allows developers to write clean, readable templates using double curly brace syntax (e.g., {{name}}) to insert variables and simple expressions, and it is designed to separate the logic from the presentation layer. Handlebars encourages keeping business logic in JavaScript and using templates purely for layout and structure.
It supports features like conditionals ({{#if}}), loops ({{#each}}), partials (reusable template fragments), and custom helpers (for reusable logic).
Handlebars can be used in both client-side (browser) and server-side (for example, Node.js with Express) environments, making it a versatile choice for rendering dynamic content in web applications, static site generators, and even email templates.
Simple example to demonstrate Handlebars
In the example, I have used the CDN link to manage the Handlebars, and of course, we can download the script and use it too!
Note: In the below example we see type=”text/x-handlebars-template”, this is to->
Keep template code inside HTML for simplicity (small projects or demo purposes).
Prevent the browser from trying to execute it as JavaScript
In the example below, we have a Handlebars.html file where the template for Handlebars starts from a script tag as in line #10, and this is rendered with the script in line #16. This gets the template by ID, compiles the template, and generates the HTML and outputs it to the browser.
When to use Handlebars?
1. Server-side rendering in Node.js (may be with Express)
Use Handlebars to render HBS views with dynamic data like dashboards or user profiles.
Clean and clear separation of the controller, which is logic and view with templates.
Example: An Express app that renders a page like Hello, {{name}} with data from a database.
2. Generating static HTML from templates
You can choose to use Handlebars with build tools to generate static sites from templates and json or yml data.
Example: Building documentation pages or blog posts from content files.
3. Dynamic HTML emails
Email templates often need dynamic content like user name, order details, etc.
Handlebars is widely supported in email-sending tools like Nodemailer.
Example: While showing some information like:
Hi {{firstName}}, your order {{orderNumber}} has shipped!
4. Rendering content in the browser from external JSON
When you want to fetch data via JavaScript and display it using a template.
Example: An order listing that loads items from the order.json file may be displayed on the UI.
5. When using simple templating without full front-end frameworks
If your app doesn’t need heavy frameworks like React or Vue, Handlebars is lightweight and easy to use.
Example: A dashboard or admin panel with dynamic content, but not so much interactivity.
When to avoid the usage of Handlebars
Okay, let’s understand when to prevent the usage of Handlebars:
When we have a complex UI with interactive states, then maybe go with component-based frameworks like Angular, React, or Vue.
When you need reactive data binding.
While building a single-page application.
When the application needs more control over visuals and interactions.
Let’s have a look at a simple example below:
Handlebars.html file
Template.hbs
Data.json
Output screen
Run the html file with Live Server extension of VS Code (if you run this example directly in the browser, fetch() won’t work! ), and here is the output:
Conclusion
Use Handlebars when we want simple, maintainable, logic-less templates for generating HTML — especially in server-side apps, static site generators, news articles, and emails.
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