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Notes on Stack vs Heap Memory

Memory Allocation for Data Types​

Stack Memory​

  • Purpose: Used for storing primitive data types.
  • Behavior: Variables get a copy of the value.
  • Example: 
    let hero = 'Batman';
    let friend = hero;
    // `friend` gets a copy of the value of `hero`, not a reference.

Heap Memory​

  • Purpose: Used for storing non-primitive data types (e.g., objects, arrays).
  • Behavior: Variables store a reference to the object.
  • Example: 
    let student = { name: 'Batman' };
    let tutor = student;
    // `tutor` gets a reference to `student`. Changing properties of `tutor` will also affect `student`.

Key Differences​

  1. Stack Memory:

    • Fast access.
    • Stores primitive types like string, number, boolean, null, undefined, symbol, bigint.
    • Each variable operates independently with its own copy of data.

  2. Heap Memory:

    • Slower access compared to stack.
    • Stores non-primitive types like objects, arrays, functions.
    • Variables share references to the same memory location.