What is the difference between unknown and any in TypeScript?

In TypeScript, any and unknown are types that can contain values of any type, but there are important differences:

• any disables type checking. A variable with type any can be assigned anywhere and used without restrictions. This reduces type safety.

• unknown is a safer alternative to any. A value of type unknown can only be assigned to a variable of type unknown or any. To use an unknown value, you must first check its type or cast it to the required type.

Example:

let a: any = 10;
let u: unknown = 10;

let num1: number = a; // OK
// let num2: number = u; // Compilation error

if (typeof u === 'number') {
  let num2: number = u; // OK after check
}

Thus, unknown forces the developer to explicitly check types, increasing code safety, while any disables all checks.