What is the difference between the 'any' and 'unknown' types in TypeScript?

The any and unknown types in TypeScript both allow storing values of any type, but they differ in safety and control levels.

• any completely disables type checking. A variable with type any can be assigned anything, and any operations can be performed on it without compilation errors. This reduces safety and the benefits of typing.

• unknown is a safer alternative to any. It can also hold a value of any type, but before using the value, a type check or type assertion must be performed. This forces the developer to explicitly handle possible cases and prevents errors.

Example:

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

// Method call without errors for any
console.log(a.toFixed(2));

// For unknown, type check is needed first
if (typeof u === 'number') {
  console.log(u.toFixed(2));
}

Thus, unknown is recommended when you need to accept values of any type but want to maintain type safety, whereas any is suitable when maximum flexibility without checks is required.