Explain the differences between the keywords let and const in JavaScript.

let and const are keywords for declaring variables in JavaScript with block scope.

• let: declares a variable whose value can be changed after initialization.

• const: declares a constant whose value cannot be reassigned after initialization.

Important:

• const does not make an object or array immutable, it only prevents reassignment of the variable itself.

Example:

let a = 5;
a = 10; // allowed

const b = 3;
// b = 4; // error

const obj = { x: 1 };
obj.x = 2; // allowed, property of object is changed
// obj = {}; // error

Thus, let is used for variables that can change, and const for values that should not be reassigned.