JavaScript Me Memory Management & Garbage Collection Kya Hota Hai?

1. JavaScript Memory Lifecycle

JavaScript mein memory ka lifecycle 3 main stages me divide hota hai:

1. Allocation (Memory Reserve Karna): Jab aap variables ya objects banate hain, JavaScript unke liye memory allocate karta hai.
2. Usage (Memory Ka Istemaal): Program ke dauran uss memory ko read ya write kiya jaata hai.
3. Release (Deallocation): Jab memory ki zaroorat nahi hoti, toh Garbage Collector use free kar deta hai.

2. Garbage Collection in JavaScript

JavaScript engine me ek Garbage Collector (GC) hota hai jo automatically "unreachable" objects (jinka koi reference nahi bacha) ko dhoondh kar unki memory ko free kar deta hai.

Mark-and-Sweep Algorithm

Modern browsers Mark-and-Sweep algorithm ka use karte hain. Yeh global objects (jaise 'window' browser me) se shuru hokar sabhi reachable objects ko "mark" karta hai. Iske baad, jo bhi objects marked nahi hote, unhe "sweep" (delete) kar diya jaata hai.

3. Memory Leaks in JavaScript

Memory leak tab hota hai jab program unused memory ko release nahi kar paata. Isse application slow ya crash ho sakti hai.

Common Causes:

• Accidental Global Variables: Bina `let`/`const` ke variable declare karna.
• Uncleared Timers: `setInterval` ko `clearInterval` se na rokna.
• Detached DOM Elements: DOM se element hata dena par uska reference JavaScript me rakhna.