What is the difference between let, const, and var?

var: Function-scoped, can be redeclared and updated, hoisted with undefined initialization.

let: Block-scoped, cannot be redeclared in same scope, can be updated, hoisted but not initialized (temporal dead zone).

const: Block-scoped, cannot be redeclared or updated, must be initialized at declaration, hoisted but not initialized.

Example:
var a = 1; // function scoped
let b = 2; // block scoped
const c = 3; // block scoped, immutable