Uncover five mysteries of JS caching mechanism
Revealed: Five mysteries of JS caching mechanism, specific code examples are required
Introduction:
When developing front-end web applications, we often encounter data Problems such as slow loading and freezing. In order to optimize the user experience and improve the loading performance of web pages, we can use JavaScript's caching mechanism. This article will reveal the five mysteries of the JS caching mechanism, along with specific code examples to help developers better understand and apply them.
1. HTTP caching mechanism
HTTP caching is one of the most commonly used caching mechanisms in web development. It uses the browser's cache to store static resources in web pages, such as images, style sheets, and script files. When the browser requests the same resource again, it reads it from the cache first instead of downloading it directly from the server.
In order to implement HTTP caching, the server will set fields such as Cache-Control and Expires in the response header. Specific code examples are as follows:
// Cache-Control设置缓存策略为public,表示所有用户(包括代理服务器)都可以缓存该资源 response.setHeader('Cache-Control', 'public'); // 设置缓存过期时间为1小时(以秒为单位) response.setHeader('Expires', new Date(Date.now() + 3600000).toUTCString());
2. LocalStorage cache
localStorage is a client-side storage solution provided by HTML5, which can save key-value pair data locally in the browser. Using localStorage to cache data can reduce network requests and improve application response speed.
The following is a sample code using localStorage cache:
// 将数据保存到localStorage中 localStorage.setItem('data', JSON.stringify(data)); // 从localStorage中读取数据 const cachedData = JSON.parse(localStorage.getItem('data'));
3. sessionStorage cache
sessionStorage is also a client storage solution provided by HTML5. It is similar to localStorage, but it saves The data is only valid during the current session. When the browser window is closed, the data in sessionStorage will be cleared.
The following is a code example for sessionStorage cache:
// 将数据保存到sessionStorage中 sessionStorage.setItem('data', JSON.stringify(data)); // 从sessionStorage中读取数据 const cachedData = JSON.parse(sessionStorage.getItem('data'));
4. Service Worker cache
Service Worker is a JavaScript script running environment provided by the browser that is independent of the web page and can intercept the network Request and cache the response. Using Service Worker caching, we can implement offline browsing functionality and provide a better user experience.
The following is a code example that uses Service Worker to cache static resources:
// 注册Service Worker navigator.serviceWorker.register('sw.js').then(registration => { console.log('Service Worker 注册成功!'); }).catch(error => { console.error('Service Worker 注册失败:', error); }); // 缓存静态资源 self.addEventListener('install', event => { event.waitUntil( caches.open('my-cache').then(cache => { return cache.addAll([ '/', '/index.html', '/style.css', '/script.js', '/image.png' ]); }) ); }); // 从缓存中读取资源 self.addEventListener('fetch', event => { event.respondWith( caches.match(event.request).then(response => { return response || fetch(event.request); }) ); });
5. Memoization (memory)
Memoization is an optimization technology that caches the calculation results of functions. Improve performance. It is suitable for functions with the same input and the same output. By caching the results of the function, repeated calculations can be avoided and the execution efficiency of the function can be improved.
The following is a sample code using Memoization:
// 缓存函数的计算结果 const memoize = fn => { const cache = new Map(); return function(...args) { const key = JSON.stringify(args); if (cache.has(key)) { return cache.get(key); } const result = fn.apply(this, args); cache.set(key, result); return result; }; }; // 计算斐波那契数列 const fibonacci = memoize(n => { if (n <= 1) { return n; } return fibonacci(n - 1) + fibonacci(n - 2); });
Conclusion:
The above are the five mysteries of the JS caching mechanism and specific code examples. By rationally utilizing the caching mechanism, we can greatly improve the loading performance and user experience of web pages. I hope this article can help developers better understand and apply caching technology and optimize front-end development work.
The above is the detailed content of Uncover five mysteries of JS caching mechanism. For more information, please follow other related articles on the PHP Chinese website!

JavaScript originated in 1995 and was created by Brandon Ike, and realized the language into C. 1.C language provides high performance and system-level programming capabilities for JavaScript. 2. JavaScript's memory management and performance optimization rely on C language. 3. The cross-platform feature of C language helps JavaScript run efficiently on different operating systems.

JavaScript runs in browsers and Node.js environments and relies on the JavaScript engine to parse and execute code. 1) Generate abstract syntax tree (AST) in the parsing stage; 2) convert AST into bytecode or machine code in the compilation stage; 3) execute the compiled code in the execution stage.

The future trends of Python and JavaScript include: 1. Python will consolidate its position in the fields of scientific computing and AI, 2. JavaScript will promote the development of web technology, 3. Cross-platform development will become a hot topic, and 4. Performance optimization will be the focus. Both will continue to expand application scenarios in their respective fields and make more breakthroughs in performance.

Both Python and JavaScript's choices in development environments are important. 1) Python's development environment includes PyCharm, JupyterNotebook and Anaconda, which are suitable for data science and rapid prototyping. 2) The development environment of JavaScript includes Node.js, VSCode and Webpack, which are suitable for front-end and back-end development. Choosing the right tools according to project needs can improve development efficiency and project success rate.

Yes, the engine core of JavaScript is written in C. 1) The C language provides efficient performance and underlying control, which is suitable for the development of JavaScript engine. 2) Taking the V8 engine as an example, its core is written in C, combining the efficiency and object-oriented characteristics of C. 3) The working principle of the JavaScript engine includes parsing, compiling and execution, and the C language plays a key role in these processes.

JavaScript is at the heart of modern websites because it enhances the interactivity and dynamicity of web pages. 1) It allows to change content without refreshing the page, 2) manipulate web pages through DOMAPI, 3) support complex interactive effects such as animation and drag-and-drop, 4) optimize performance and best practices to improve user experience.

C and JavaScript achieve interoperability through WebAssembly. 1) C code is compiled into WebAssembly module and introduced into JavaScript environment to enhance computing power. 2) In game development, C handles physics engines and graphics rendering, and JavaScript is responsible for game logic and user interface.

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Dreamweaver Mac version
Visual web development tools

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
