JavaScript Memory Leak Prevention Guide I. Core Principles JavaScript employs automatic garbage collection with the mark-and-sweep algorithm to manage memory. When strong reference chains exist between objects, the garbage collector cannot identify the objects to be reclaimed, leading to memory leaks. Common scenarios include: event listeners for dynamically added DOM elements that are not removed, timers created with setInterval or setTimeout that are not destroyed, and closures that reference large objects. II. Prevention Strategies 1. Effective Prevention of Declared Variables That Are Not Used - Avoid declaring variables that are not used - Ensure variable lifetimes and scopes match when using let/const 2. Optimizing Resource Release - Clear timers created with setInterval or setTimeout - Remove event listeners from dynamically added DOM elements - Manage large objects using weak references (WeakRef) 3. Precise Identification of Leak Sources - Analyze memory snapshots using Chrome DevTools Memory panel - Monitor memory usage trends via Performance API - Use Memory Profiler tools to locate memory leak hotspots III. Common Scenarios 1. Routing in Single Page Applications (SPA) - Event listeners are not removed when route components are unloaded - Accumulation of unused component instances 2. Large Object References - Closures that continuously reference large objects - Unreleased DOM elements IV. Best Practices 1. Implementing Resource Release Mechanisms - Use explicit cleanup functions (e.g., onBeforeUnmount) - Utilize Promise.all for asynchronous resource cleanup 2. Optimizing Code Structure - Avoid nested scopes - Implement modular design to separate resource management 3. Adopting Modern Development Tools - Utilize TypeScript's optional type annotations to identify potential leaks - Configure ESLint to detect unused variables Notes: Modern browsers have largely resolved cycle references, but unnecessary strong references should still be avoided. Recommended practices include using WeakMap/WeakSet to manage large object references, ensuring efficient memory resource management. Note: Modern browsers have largely resolved cycle reference issues, but unnecessary strong references should still be avoided. Recommended practices include using WeakMap/WeakSet to manage large object references, ensuring efficient memory resource management.