Defining classes

Classes are in fact "special functions", and just as you can define function expressions and function declarations, the class syntax has two components: class expressions and class declarations.

Class declarations

One way to define a class is using a class declaration. To declare a class, you use the class keyword with the name of the class ("Rectangle" here).

An important difference between function declarations and class declarations is that function declarations are hoisted and class declarations are not. You first need to declare your class and then access it, otherwise code like the following will throw a ReferenceError

An important difference between function declarations and class declarations is that function declarations are hoisted and class declarations are not. You first need to declare your class and then access it, otherwise code like the following will throw a ReferenceError

Class expressions

A class expression is another way to define a class. Class expressions can be named or unnamed. The name given to a named class expression is local to the class's body. However, it can be accessed via the name property.