JavaScript's memory management is mostly automatic, but knowing how it works can help you write more efficient code.
Stack vs. Heap
- Stack: Stores primitive types and references
- Heap: Stores objects and functions
let name = "Alice"; // Stack
let user = { name: "Bob" }; // Reference in stack, object in heap
Memory Allocation
JavaScript automatically allocates memory when objects are created and frees it when they're no longer used.
Garbage Collection
Two main strategies:
- Reference counting (outdated)
- Mark and sweep (modern)
let obj = { data: "some data" };
obj = null; // Object becomes eligible for garbage collection
Common Pitfalls
- Accidental global variables
- Forgotten timers or callbacks
- Closures holding large scopes
Best Practices
- Use
const
andlet
instead ofvar
- Nullify references to large objects when done
- Be cautious with closures in long-running functions
Tools for Memory Analysis
- Chrome DevTools Memory panel
- Node.js --inspect flag
Understanding the memory model helps in writing performant JavaScript. Always profile before optimizing.
Hope this helps. Cheers🥂