Node.js+koa builds a simple backend management system

Micro front-end is an architectural concept that splits large front-end applications into multiple independent modules. Its core advantages include flexible technology stacks, independent deployment iteration, improving team collaboration efficiency, and supporting incremental upgrades. Common implementation methods include iframe, WebComponents encapsulation, ModuleFederation, SingleSPA framework, etc. At the same time, you need to pay attention to issues such as routing coordination, style isolation, state sharing and performance optimization.

CommonJS and ESModules are two mainstream module systems of JavaScript, suitable for different scenarios and have compatibility issues. 1. CommonJS is an early standard for Node.js. It uses require() to load modules simultaneously, which is suitable for traditional back-end services and old projects; 2. ESModules is a modern standard, which uses import asynchronous loading, supports static analysis and TreeShaking, which is suitable for new projects and modern engines; 3. The two can coexist but have limited interoperability. It is recommended to unify module types or standardize through packaging tools; 4. When integrating JS modules in Java microservices, you need to pay attention to the support of the module system and the consistency of the construction process of the operation environment.

Java uses a class-based inheritance model, while JavaScript relies on prototype chains to implement inheritance. In Java, a class is an object template, an instance inherits the properties and methods of the parent class, and the inheritance relationship is determined at compile time; while in JavaScript, the object directly inherits other objects, and dynamically searches properties and methods through the prototype chain, which has higher flexibility. For example, JavaScript allows the runtime to modify prototypes, affecting all relevant instances, while Java needs to be recompiled. Although ES6 introduced class syntax to make JavaScript more like Java, its underlying layer is still based on the prototype mechanism.

Generator function is a special function defined using function*, which can be paused and resumed execution through yield. Returns the generator object when called, and executes each yield step by step through .next(), returning {value, done}; yield can receive input such as .next(value). Common uses include custom iterative logic, lazy evaluation (such as infinite Fibonacci sequences), and historical asynchronous process control. Note: After the generator is completed, .next() returns undefined and done:true, and can be used to end .return() in advance or .throw() throw errors. Despite the popularity of async/await, generators are in state machines and other fields

The execution mechanism of JavaScript is centered on event loops to solve the problem of asynchronous task scheduling. Its key structure includes call stack, heap and message queue: 1. The call stack records the functions being executed; 2. The heap stores object data; 3. The message queue stores asynchronous callbacks. The event loop distinguishes macro tasks from micro tasks, such as setTimeout, setInterval, I/O and UI rendering, and micro tasks such as Promise.then/catch/finally, queueMicrotask and MutationObserver. Each loop executes a macro task first, and then clears all micro tasks. For example, Promise.then as a micro task will be in

FeaturePolicies(PermissionsPolicy)allowcontroloverJavaScriptbehaviorsbyselectivelyenablingordisablingbrowserfeaturesandAPIs.Tousethem,setanHTTPheaderlikePermissions-Policy:geolocation=(),fullscreen=(self)torestrictaccessbasedondomain.Youcanlimitcapab

Automated JavaScript accessibility testing tools can effectively improve the efficiency of front-end barrier-free detection. 1. Tools such as axe-core, pa11y and LighthouseCLI integrated into the development process can automatically check problems in CI/CD; 2. Browser plug-ins such as axeDevTools and WAVE provide real-time debugging and intuitive feedback; 3. In unit testing, jest-axe and TestingLibrary can be combined to verify accessibility standards at the component level, helping developers establish a complete barrier-free testing process at different stages.

WebGPU is a new generation of APIs for high-performance graphics and computing in modern browsers. It is more underlying and efficient than WebGL, and supports modern GPU functions. 1. Pipeline state object (PSO) is the core of the rendering pipeline. It should be created and reused in advance, and different pipelines should be customized according to needs to improve performance; 2. Use bindgroup and bindgrouplayout to organize resource binding, reasonably divide resource groups, avoid frequent updates of buffers, and use dynamic offsets to process instance data to improve efficiency; 3. WGSL is the default shading language of WebGPU, with strict syntax and strong type, and pay attention to memory alignment rules, making it clearer and safer after familiarity; 4. Multi-buffer management and synchronization mechanism are crucial, and multi-frame buffering is used.