Implementing interfaces and types

A class can implement an interface or type alias in the exact same way. But it cannot implement (or extend) a type alias that names a union type. For example:

// Implementing an interface
interface IWork {
  company: string
  position: string
}
class Person implements IWork {
  name: 'Carlos'
  age: 35
}
// Implementing a type
type TWork = {
  company: string
  position: string
}
class Person2 implements TWork {
  name: 'Cristina'
  age: 34
}
// You can't implement a union type
type TWork2 = {   company: string;   position: string } | {   name: string;   age: number } 
class Person3 implements TWork2 {
  company: 'Google'
  position: 'Senior Software Engineer'
}

If you write the preceding code, you will get the following error in your editor:

Figure 2.3: A class can only implement an object type or intersection of object types with statically known members

As you can see, you are not able to implement a union type.