Checking Types

Sometimes we want to check the type of a value at runtime.

For primitive types and functions, we do this by accessing the name of the type using the typeof keyword.

For object types, there isn't a single best approach, but we'll look at a couple.

Primitive type names

We can find the type name of a primitive or function value using the typeof operator:

Checking object types

We typically use the instanceof operator to compare an object value with its constructor.

However, there are some edge cases where we may rely on special library methods like Array.isArray instead.

Object type names

Generally we should use instanceof, but we can find the type name of an object value if we really want to.

Note that this runs much more slowly than typeof or instanceof.