Learn React with TypeScript 3

Abstract classes

Abstract classes are a special type of class that can only be inherited from and not instantiated. They are declared with the abstract keyword, as in the following example:

1. We can define a base Product class as follows:

abstract class Product {  name: string;  unitPrice: number;}

2. If we try to create an instance of this, the compiler will complain, as we would expect:

3. We can create a more specific usable class for food products by extending Product:

class Food extends Product {  constructor(public bestBefore: Date) {    super();  }}

4. Here, we are adding a bestBefore date in our Food class. We can then create an instance of ...