What is the difference between “”let”” and “”var””?

In JavaScript, let and var are both used to declare variables, but they differ in scope and behavior:

1. Scope:

var has function scope or global scope (if declared outside a function), meaning it’s available throughout the entire function or globally.

let has block scope, meaning it is only accessible within the block (e.g., loops, conditionals) where it is defined.

2. Hoisting:

var is hoisted to the top of its scope, meaning it is available before its declaration, but it is initialized with undefined.

let is also hoisted, but it is not initialized. Accessing it before its declaration results in a ReferenceError.

3. Re-declaration:

var allows re-declaration within the same scope without any error.

let does not allow re-declaration within the same scope.

In modern JavaScript, let is generally preferred for its block scoping and safer behavior.