ECMAScript defines 8 data types: Undefined, Boolean, Number, Null, BigInt, String, Object, Symbol.
It is important to note that the typeof operator can return values that do not comply with the standard.
The typeof operator returns the string 'function' for functions, although ECMAScript does not define this type. This is done for convenience.
Also typeof returns the string 'object' for null. This error is not fixed intentionally, so as not to break backward compatibility for already written code.