The answer
Automatically. The engine allocates memory (stack for primitives, heap for objects), you use it, and the garbage collector frees unreachable memory. You do not manually allocate or free memory like in C/C++.
Memory Management in JavaScript: A Complete Guide
How does memory management work in JavaScript?
More FAQs in Memory Management in JavaScript: A Complete Guide
Stack stores primitives and references (fast, LIFO, per-function frames). Heap stores objects, arrays, and functions (unstructured, managed by the GC). Variables hold references to heap objects.
Accidental globals (x = 5 without let), forgotten timers (setInterval never cleared), event listeners on detached DOM elements, closures keeping large objects alive, unbounded caches, and detached DOM references.
Chrome DevTools Memory tab (take heap snapshots, compare). Performance tab (record memory over time, look for growth). performance.memory.usedJSHeapSize (Chrome only). process.memoryUsage() in Node.js.
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