File system exclusion rules

Vitejs file system exclusion rules control file access permissions through the configuration of `server.fs.deny` or `fs.allow` options, supporting three matching methods: strings, regular expressions, and functions. These rules are used to protect sensitive files, improve performance, avoid cache pollution, and enhance security. Typical applications include excluding `.env` files, log files, or system directories. The development server uses these rules, while production builds require coordination with Rollup configuration. Common issues include rules not taking effect or being overly restrictive, which can be diagnosed by enabling debug mode to view exclusion details. Advanced techniques include dynamic exclusions, environment variable control, and plugin interaction. For performance optimization, prioritize simple matching and avoid synchronous I/O operations. Exclusion rules affect module resolution but can preserve type definitions. During debugging, enable `server.debug` to view detailed matching information.

Build output directory structure control

Vite.js provides flexible build options through vite.config.js. The default configuration file automatically loads basic settings, including development server setup, build options, and environment variable handling. Environment variables are managed via .env files and are accessible in the code. The build output directory defaults to 'dist' but can be modified. Static assets support subdirectories and file hashing. Multi-page applications can be achieved by configuring different directory structures. Custom build logic includes library mode, path aliases to simplify imports, and a public base path that affects resource prefixes. Build target configurations ensure browser compatibility, while code-splitting strategies optimize performance. Custom HTML output controls the structure. Environment-specific configurations distinguish between development and production builds. Build analysis optimizes size, and source map configurations support debugging. External dependencies can be excluded, and multi-format outputs ensure compatibility with different modules. Build hooks extend functionality, and file system caching improves speed. Build reports monitor size, and custom middleware enhances the development server. Build time optimizations reduce waiting, and multiple environment variable files support different scenarios.

Development server options configuration

The ViteJS configuration file `vite.config.js` is located in the project root directory and customizes build behavior through `defineConfig`. Common basic configurations include `root`, `base`, `publicDir`, and `cacheDir`. The development server is configured via the `server` option, supporting host, port, proxy, HTTPS, and filesystem restrictions. HMR configuration allows disabling the error overlay or customizing the connection. Pre-build options optimize dependency handling. Environment variables can define values like `APP_VERSION`. The build target supports different browsers. Advanced server configurations enable polling and multi-environment handling. The plugin system integrates Vue and legacy plugins. Performance optimization configurations include compression and chunking. Custom build logic extends Rollup configurations. Debugging configurations support sourcemap filtering and Inspector debugging.

Global variable injection method

Vitejs provides multiple global variable injection methods for project configuration and environment variable sharing. Environment variables are exposed through the `import.meta.env` object and must be prefixed with `VITE_` to be accessible on the client side. Server-side variables use `process.env`. The `define` option in `vite.config.js` can inject compile-time constants. CSS preprocessor variables are injected via the `additionalData` option. Module global registration is achieved using `vite.plugin.global` for auto-import. Custom plugins enable flexible injection. Client-side type support requires adding TypeScript declarations. Multi-environment differentiated configurations combine environment variables for dynamic imports, leveraging global variables. Be cautious to avoid injecting sensitive information, disable debug variables in production, and follow naming conventions with uppercase and underscores. Frontend variables must be prefixed with `VITE_`.

Custom HTML template

ViteJS allows developers to customize HTML templates to meet different needs through simple configuration, enabling the overriding of default templates. The article details basic configuration methods, including creating custom HTML files and using template variable interpolation. It also covers multi-page application configuration, dynamic template generation, and resource reference handling. Additionally, it discusses conditional content injection, template location customization, CSS processing, SSR configuration, internationalization support, performance optimization, security settings, mobile adaptation, PWA support, favicon setup, social media optimization, template fragment reuse, build-time variable substitution, cache control, error page customization, template compression, environment-specific content, SVG handling, web component usage, and template debugging techniques. This provides developers with a comprehensive guide to HTML template customization.

Build target and multi-page application configuration

Vite.js, as a modern front-end build tool, is favored by developers for its fast startup and hot module replacement capabilities. Project initialization can be completed with simple commands. The core configuration file, vite.config.js, includes a plugin system, development server, and basic settings for the build output directory. The build target configuration supports multiple output formats, allows setting browser compatibility, and enables detailed configuration of the output directory and static resource paths. Multi-page application configuration requires more complex setups, including dynamically generating configurations and custom page templates. Advanced techniques involve shared dependencies, environment variable integration, and performance optimization. Special configurations for the development server include proxy settings and hot updates. Vite can also seamlessly integrate with other tools like TailwindCSS and PWA. Common issues include routing conflicts and static resource path problems, along with their solutions.

Analysis of New Features in Webpack 5

Webpack 5 introduced the Module Federation feature, revolutionizing the implementation of micro-frontend architectures by allowing code sharing between different builds without traditional bundling methods. One application can dynamically load another application's code while maintaining independent builds and deployments. The persistent caching mechanism was improved, with file system caching enabled by default, significantly speeding up secondary builds. Four new asset module types were added to replace loaders like `file-loader`, simplifying configuration. Build optimization flags provide finer-grained control, and the Tree Shaking mechanism was enhanced with better nested exports handling and improved CommonJS support. Performance analysis tools now offer more detailed insights, and support for the `exports` field in `package.json` enables precise export control. WASM synchronous loading simplifies usage workflows, while build difference reports help analyze changes. The configuration syntax became more flexible, supporting dependency declarations to resolve multi-application conflicts.

Implementation details of Tree Shaking in Webpack

Webpack's Tree Shaking eliminates unused code through static analysis by leveraging the static structure characteristics of ES Module. Its implementation requires: - Using ES2015 module syntax without converting to CommonJS modules - Adding `sideEffects` declarations - Enabling the `usedExports` configuration The core principles include: - Building a module dependency graph - Marking used exports - Optional scope hoisting - Handling side effects via `/*#__PURE__*/` annotations and `sideEffects` configuration Babel must preserve ES modules to avoid breaking Tree Shaking. Dynamic imports require special configuration, and third-party libraries can be optimized via `resolve`. Debugging can be done using `stats` output. Common issues involve CSS removal and TypeScript enum handling. Advanced techniques include code sharing, manual marking, and performance monitoring via `performance` configuration.

The principle of Webpack's Hot Module Replacement

Webpack's Hot Module Replacement (HMR) feature allows runtime module updates without a full refresh, enhancing the development experience. Its workflow includes file monitoring, compilation, update message notification, and module replacement. The HMR runtime consists of a RuntimeServer and interfaces that communicate via WebSocket. Different update strategies are applied for various module types, such as JavaScript, styles, and React components. Webpack provides multiple update methods through the `module.hot` API, with implementation details involving module ID mapping and reference updates. HMR supports scenarios like CSS and React, with optimization techniques including incremental builds and caching. However, it has limitations such as state loss. Developers can customize its behavior. The HMR mechanism shares similarities with production environment persistent caching.

The code generation process of Webpack

The code generation process in Webpack is the core part of its bundling mechanism. First, it constructs a complete dependency graph based on the entry file and processes the interdependencies between modules through the `compilation` object. After dependency analysis, modules are divided into different chunk types. Each module is wrapped in a function closure and loaded using the `webpack_require` system. The runtime environment is injected, including critical components like the module caching system and asynchronous loading logic. During the code generation phase, various optimization strategies are applied, such as Tree Shaking and Scope Hoisting. The final bundle includes essential parts like the bootstrap program and module mapping. Advanced feature handling involves transforming dynamic imports into asynchronous loading and implementing Hot Module Replacement (HMR). Performance optimization strategies include module ID optimization and shared code extraction. Additionally, the code generation process can be customized through plugins to intervene in the bundling results.