Intersection Types in TypeScript

Intersection types allow us to combine other types.

Say, we have an interface for Person:

interface Person {
  name: string;
  gender: string;
}

There is also an another interface for Farmer:

interface Farmer {
  crop: string;
}

Now, for some reasons we need a new interface that contains the properties of both Person and Farmer. One option is to list out all properties again as shown below:

interface PersonFarmer {
  name: string;
  gender: string;
  crop: string;
}

Or, we can use intersection operator like below:

type PersonFarmer = Person & Farmer;

Note that we need to use type when we use intersection operator. Instead of type, if we need to use interface for PersonFarmer, then we can consider extending Person and Farmer.