Express App and Handlebars

What is Express App?

Express is a web application framework for Node.js that offers a wide range of functionality for developing mobile and web applications. It is employed in the development of hybrid, multipage, and single-page web applications. It is a layer that assists in managing servers and routes and is built on top of Node.js.

Key Features of Express App

• Routing: Express makes it easier to define routes that are used to handle HTTP requests. For various HTTP methods (GET, POST, PUT, DELETE, etc.), you can design routes and handle them appropriately.
• Middleware: In Express, middleware functions are those that have access to the response and request objects. They have the ability to alter these objects, run any code, end the request-response loop, and transfer control to the following middleware function. For activities like error handling, logging, and authentication, among others, middleware functions are helpful.
• Template Engines: Although Express lacks a built-in template engine, you can integrate well-known ones like EJS, Pug, Handlebars, and others to create dynamic HTML content.
• Serving Static Files: Express's express.static middleware makes it simple to serve static files, such as HTML, CSS, pictures, and so on.
• Error Handling: When an error arises while the application is running, Express offers ways to handle it. To detect issues and take the necessary action, you can construct middleware functions that handle errors.
• Middleware & Route Parameters: With Express, you may specify middleware and route parameters that your route handlers can utilize to retrieve data from the request body or request URL.
• Handling HTTP Responses: You have complete control over the HTTP responses that Express returns to the client. You can send several kinds of answers (JSON, HTML, text, etc.) and configure headers, cookies, and status codes.
• Connect Middleware Framework Integration: Express is based on the Connect Middleware framework, which offers a suite of high-performance middleware for developing web servers. Connect middleware may be easily integrated with Express.
• Modular Structure: For improved maintainability and scalability, express applications can be modularly designed, with routes, middleware, and other components arranged into distinct modules or files.
• WebSocket Support: Although the main focus of Express is on HTTP, it may be expanded to facilitate WebSocket communication by utilizing libraries such as Socket.IO or ws.

Basic Structure of Express App

• Import the express module to create an Express application.
• Using the respective handler functions and HTTP methods (GET, POST, PUT, and DELETE), define routes.
• Open a port and listen to it to start the server.

What is a Handlebar?

JavaScript is used to create the HTML templating engine Handlebar. It works to create dynamic HTML pages. It is used with Node.js-based client-side and server-side applications. By enabling the integration of variables and logic into templates, it simplifies the process of producing dynamic HTML.

Key Features of Handlebars

• Logic-Less Templates: Handlebars do not include programming logic such as loops or conditions; instead, they concentrate on placeholders and helpers.
• Expressions: Use expressions encased in double curly braces to insert dynamic content.
• Helpers: Use JavaScript functions to customize functionality, manipulate data, or produce intricate output.
• Partial Views: Make reusable elements that divide the user interface into smaller, more manageable chunks and utilize them in other views.
• Block Helpers: Create unique logic blocks for complex operations, iteration, and conditional rendering.
• Whitespace Control: An integrated feature to preserve the formatting of HTML that is generated.
• HTML Escaping: To thwart XSS attacks, HTML entities are automatically escaped.
• Integrated Helpers: Contains standard aids for operations such as conditional rendering and iteration.
• Middleware Integration: For server-side rendering, it integrates with Express.js with ease.
• Help for Client-Side Apps: Allows templates to be precompiled for usage in client-side browser applications.

Basic Usage of HandleBars

• Define templates for Handlebars using the.hbs extension.
• Use the double curly brackets {{ }} to insert variables.
• For handling logic, use control structures such as #if, #each, and #unless.
• If necessary, register and make use of custom helper functions.

Integration with Express

• Install the npm packages express-handlebars and handlebars.
• Set Handlebars as the view engine for Express.
• Use res.render() to render Handlebars templates in Express routes.