JavaScript Memory Leak Fix: 6 Patterns + DevTools Walkthrough
Every memory leak tutorial tells you to open DevTools without giving you actual leaks to practice on. This guide has 6 live triggerable leaks built into the demo — open DevTools alongside and watch memory grow in real time. Covers the three-snapshot technique, queryObjects() DevTools trick, observer-disconnect (ResizeObserver / IntersectionObserver), AbortController unified cleanup, performance.measureUserAgentSpecificMemory() for production, React useEffect cleanup, WeakMap/WeakRef + FinalizationRegistry caveats, and real KB-per-minute growth numbers.