conditional type

컨티셔널 타입

SomeType extends OtherType ? TrueType : FalseType;

interface Animal {
  live(): void;
}
interface Dog extends Animal {
  woof(): void;
}

type Example1 = Dog extends Animal ? number : string;
//   ^ = type Example1 = number

type Example2 = RegExp extends Animal ? number : string;
//   ^ = type Example2 = string