How to compile JavaScript

React itself does not directly manage focus or accessibility, but provides tools to effectively deal with these issues. 1. Use Refs to programmatically manage focus, such as setting element focus through useRef; 2. Use ARIA attributes to improve accessibility, such as defining the structure and state of tab components; 3. Pay attention to keyboard navigation to ensure that the focus logic in components such as modal boxes is clear; 4. Try to use native HTML elements to reduce the workload and error risk of custom implementation; 5. React assists accessibility by controlling the DOM and adding ARIA attributes, but the correct use still depends on developers.

Shallowrenderingtestsacomponentinisolation,withoutchildren,whilefullrenderingincludesallchildcomponents.Shallowrenderingisgoodfortestingacomponent’sownlogicandmarkup,offeringfasterexecutionandisolationfromchildbehavior,butlacksfulllifecycleandDOMinte

StrictMode does not render any visual content in React, but it is very useful during development. Its main function is to help developers identify potential problems, especially those that may cause bugs or unexpected behavior in complex applications. Specifically, it flags unsafe lifecycle methods, recognizes side effects in render functions, and warns about the use of old string refAPI. In addition, it can expose these side effects by intentionally repeating calls to certain functions, thereby prompting developers to move related operations to appropriate locations, such as the useEffect hook. At the same time, it encourages the use of newer ref methods such as useRef or callback ref instead of string ref. To use Stri effectively

Server-siderendering(SSR)inNext.jsgeneratesHTMLontheserverforeachrequest,improvingperformanceandSEO.1.SSRisidealfordynamiccontentthatchangesfrequently,suchasuserdashboards.2.ItusesgetServerSidePropstofetchdataperrequestandpassittothecomponent.3.UseSS

WebAssembly(WASM)isagame-changerforfront-enddevelopersseekinghigh-performancewebapplications.1.WASMisabinaryinstructionformatthatrunsatnear-nativespeed,enablinglanguageslikeRust,C ,andGotoexecuteinthebrowser.2.ItcomplementsJavaScriptratherthanreplac

Vite or VueCLI depends on project requirements and development priorities. 1. Startup speed: Vite uses the browser's native ES module loading mechanism, which is extremely fast and cold-start, usually completed within 300ms, while VueCLI uses Webpack to rely on packaging and is slow to start; 2. Configuration complexity: Vite starts with zero configuration, has a rich plug-in ecosystem, which is suitable for modern front-end technology stacks, VueCLI provides comprehensive configuration options, suitable for enterprise-level customization but has high learning costs; 3. Applicable project types: Vite is suitable for small projects, rapid prototype development and projects using Vue3, VueCLI is more suitable for medium and large enterprise projects or projects that need to be compatible with Vue2; 4. Plug-in ecosystem: VueCLI is perfect but has slow updates,

Immutable updates are crucial in React because it ensures that state changes can be detected correctly, triggering component re-rendering and avoiding side effects. Directly modifying state, such as push or assignment, will cause React to be unable to detect changes. The correct way to do this is to create new objects instead of old objects, such as updating an array or object using the expand operator. For nested structures, you need to copy layer by layer and modify only the target part, such as using multiple expansion operators to deal with deep attributes. Common operations include updating array elements with maps, deleting elements with filters, adding elements with slices or expansion. Tool libraries such as Immer can simplify the process, allowing "seemingly" to modify the original state but generate new copies, but increase project complexity. Key tips include each

Front-end applications should set security headers to improve security, including: 1. Configure basic security headers such as CSP to prevent XSS, X-Content-Type-Options to prevent MIME guessing, X-Frame-Options to prevent click hijacking, X-XSS-Protection to disable old filters, HSTS to force HTTPS; 2. CSP settings should avoid using unsafe-inline and unsafe-eval, use nonce or hash and enable reporting mode testing; 3. HTTPS-related headers include HSTS automatic upgrade request and Referrer-Policy to control Referer; 4. Other recommended headers such as Permis