TypeScript Tutorial #5 - The 'Any' Type

#Any

Let's first look at any type so that we can better understand the motivation behind introducing the unknown type.

Any type has been in TypeScript since the first release in 2012. It represents all possible JavaScript values — primitives, objects, arrays, functions, errors, symbols, what have you.

In TypeScript, every type is assignable to any. This makes any a top type (also known as a universal supertype) of the type system.

Here are a few examples of values that we can assign to a variable of type any:

let value: any;

value = true; // OK
value = 42; // OK
value = "Hello World"; // OK
value = []; // OK
value = {}; // OK
value = null; // OK
value = undefined; // OK
value = new TypeError(); // OK
value = Symbol("type"); // OK

Any type is essentially an escape hatch from the type system. As developers, this gives us a ton of freedom: TypeScript lets us perform any operation we want on values of type any without having to perform any kind of checking beforehand.