Check out Utility Types documentation. Here’s a simple example of using the Omit utility.

I was dealing with an interface that had a required property that was itself a complex data structure with further nested objects. Kind of like this:

interface Thing {
  prop1: string;
  prop2: string;
  complexData: ComplexData
}

In my test, I didn’t need complexData at all. So, it would have been really heavy-handed to mock that data in my unit test. Using the Omit utility, I was able to create an interface with all properties except the complexData property.

type MockThing = Omit<Thing, 'complexData'>;

const thing: MockThing = {
  prop1: 'foo',
  prop2: 'bar'
}

There’s a bunch of other utilities. See the TypeScript utility types docs for all of them.