Lazy Loading Strategies

1. Introduction

Lazy loading is a design pattern that postpones the loading of non-essential resources at the point the page is rendered. This helps improve performance and user experience by reducing initial load time.

2. What is Lazy Loading?

Lazy loading refers to the practice of deferring the loading of images or other resources until they are needed, typically when they are about to be scrolled into view. This technique can significantly enhance the performance of web applications.

3. Types of Lazy Loading

• Image Lazy Loading
• Component Lazy Loading
• Route-based Lazy Loading
• JavaScript Lazy Loading

4. Implementing Lazy Loading

There are different ways to implement lazy loading depending on the resource type. Here are some methods:

4.1 Image Lazy Loading

<img src="placeholder.jpg" data-src="actual-image.jpg" class="lazy">

Use JavaScript to replace the src attribute with data-src when the image is in view.

4.2 Component Lazy Loading (React Example)

import React, { Suspense, lazy } from 'react';

const LazyComponent = lazy(() => import('./LazyComponent'));

function App() {
    return (
        <div>
            <Suspense fallback="Loading...">
                <LazyComponent />
            </Suspense>
        </div>
    );
}
        

4.3 Route-based Lazy Loading (React Example)

const LazyComponent = React.lazy(() => import('./LazyComponent'));

function App() {
    return (
        <BrowserRouter>
            <Routes>
                <Route path="/lazy" element=<LazyComponent /> />
            </Routes>
        <BrowserRouter>
    );
}
        

5. Best Practices

• Use loading="lazy" attribute for images in modern browsers.
• Implement a placeholder or skeleton screen for better user experience.
• Test lazy loading across different devices and browsers to ensure compatibility.

6. FAQ