Variables and Types

Why variables matter

Variables store values your program can reuse. In modern JavaScript you almost always use const or let.

const vs let

const appName = "Coding Dimension";
let visitCount = 0;
visitCount += 1;

• const — binding cannot be reassigned
• let — binding can be reassigned
• var — legacy; avoid in new code

Primitive types

Common primitives: string, number, boolean, null, undefined, bigint, symbol.

Use typeof to inspect a value quickly during learning and debugging.