Explain the concept of Partials/Layout templates in Express Views.

Express is a Node web application framework that simplifies the process of building web applications. One of its key features is the flexibility it offers in rendering dynamic views.

In this article, we will discuss the concept of partials or layout templates in Express views, exploring how they enhance the organization and reusability of code within your web applications.

What are Views in Express ?

In simple terms, Express views are like the architects of a webpage. They are the ones responsible for putting together all the dynamic content you see on a website when you visit it. These views are kind of like the blueprints for a webpage, made using HTML, and they have special spots where the website can put in different information depending on what it needs to show you. But, you know, as websites get more complicated, it can get a bit tricky to keep these views organized and tidy.

What are Partials/Layout Templates ?

This is where partials or layout templates come into play. They allow developers to break down views into modular components, making it easier to manage and maintain code. Think of partials as reusable building blocks that can be inserted into multiple views, promoting code reusability and maintainability.

Key Concepts Partial and Layout Views:

Partial Views:

• Express.js allows the creation of partial views, which are essentially smaller, reusable components of a larger view.
• These partials can represent specific sections of a webpage, such as headers, footers, or sidebars.
• Including a partial in a view is achieved through a simple syntax, enhancing code organization.

Layout Templates:

• Layout templates serve as the overall structure for views, providing a consistent design across multiple pages.
• They often include the common structure of a webpage, like the HTML structure, head, and body elements.
• Express.js enables the use of layout templates to wrap around individual views, ensuring a uniform look and feel.

Implementation of Partials/Layout Templates in Express:

To implement partials or layout templates in Express.js, follow these steps:

Create Partial Views:

• Identify sections of your views that can be converted into partials.
• Save these partials in a dedicated folder within your project.

Utilize Layout Templates:

• Design a layout template that encapsulates the common structure of your web pages.
• Integrate the layout template with individual views using Express.js settings.

Benefits of Partials and Layout Templates in Express:

1. Code Reusability: Partials enable the reuse of components across multiple views, reducing redundancy.
2. Easy Maintenance: Modularizing views makes it easier to maintain and update specific sections of a webpage.
3. Consistent Design: Layout templates ensure a consistent design across all pages, enhancing user experience.

By utilizing both partials and layout templates in Express.js, developers can strike a balance between code modularity and consistent design, resulting in more maintainable and user-friendly web applications.

Aspects	Partials	Layout Template
Definition	Smaller, reusable components of a view.	Overall structure for views, providing a common design.
Purpose	Represent specific sections (e.g., headers, footers).	Define the common structure for multiple pages.
Integration Syntax	Included within a view using a specific syntax.	Used to wrap around individual views.
Code Reusability	Enables reuse of components across multiple views.	Ensures consistency and uniformity in design.
Organization	Improves code organization by modularizing views.	Provides a consistent structure across pages.
Implementation Steps	Identify sections, create partials, and include them in views.	Design a template, integrate it with Express.js settings.
Benefits	Reduces redundancy, easy maintenance of specific sections.	Ensures a consistent look and feel across all pages.
Example Use Case	A partial for a comment section that appears on various pages.	A layout template defining the common structure for all pages.
Flexibility	Offers flexibility in customizing specific sections of a view.	Maintains a standard structure, offering a uniform user experience.

Steps to Implement Partial/Layout Views:

Step 1 : Install express ejs using:

npm install express ejs

Step 2 : Create an app.js for connecting express.

Step 3 : Create a folder named views in the same directory as your app.js file, and inside it, create an EJS template file named index.ejs insert the following code::

Javascript

// app.js

const express = require("express");
const app = express();
const port = 3000;

// Set EJS as the view engine
app.set("view engine", "ejs");

// Middleware to parse form submissions
app.use(express.urlencoded({ extended: true }));

// Define a route to render the template
app.get("/", (req, res) => {
    // Render the 'index' template and pass some data
    res.render("index", {
        title: "Express Templates",
        message: "Welcome to Express Templates!",
        greeting: "",
    });
});

// Handle form submissions
app.post("/", (req, res) => {
    const { name } = req.body;
    const greeting = `Hello, ${name}!`;
    // Render the 'index' template with the greeting
    res.render("index", {
        title: "Express Templates",
        message: "Welcome to Express Templates!",
        greeting,
    });
});

// Start the server
app.listen(port, () => {
    console.log(`Server is running at http://localhost:${port}`);
});

HTML

<!-- views/index.ejs -->

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>
        <%= title %>
    </title>
    <!-- Add Bootstrap CSS link -->
    <link rel="stylesheet"
          href=
"https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
    <style>
        body {
            background-color: #f8f9fa;
        }

        .container {
            margin-top: 50px;
        }

        form {
            margin-bottom: 20px;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="jumbotron">
            <h1 class="display-4">
                <%= message %>
            </h1>
            <form action="/" method="post">
                <div class="form-group">
                    <label for="name">Enter your name:</label>
                    <input type="text"
                           class="form-control"
                           id="name"
                           name="name"
                           required>
                </div>
                <button type="submit" class="btn btn-primary">Submit</button>
            </form>
            <% if(greeting) { %>
                <p class="lead">
                    <%= greeting %>
                </p>
                <% } %>
        </div>
    </div>

    <!-- Add Bootstrap JS and Popper.js scripts -->
    <script src="https://code.jquery.com/jquery-3.5.1.slim.min.js"></script>
    <script src=
"https://cdn.jsdelivr.net/npm/@popperjs/core@2.9.2/dist/umd/popper.min.js">
    </script>
    <script src=
"https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js">
    </script>
</body>

</html>

Output: