Typescript Enums and Types 03

typescript_enums_and_types_03.ts

type AnimalToPet = {
  kind: string
  target: CalicoCat | SphynxCat | Turtle
}

type Animal = {
  appearance: string
}

type CalicoCat = Animal & {
  onlyACalicoThing: string
}

type SphynxCat = Animal & {
  onlyASphynxThing: string
}

type Turtle = Animal & {}

const petCat = function(animal: AnimalToPet) {
  console.log("What kind of cat am I petting?")

  // new in TS4.6
  const { kind, target } = animal;

  if (kind === "Turtle") {
    console.log("This is not a Cat at all!")
  } else {
    console.log(target.appearance)
  }
}

const calico: CalicoCat = { 
  appearance: "Looks like a CalicoCat.",
  onlyACalicoThing: "being orange and stripey"
}
const sphynx: SphynxCat = {
  appearance: "Looks like a SphynxCat.",
  onlyASphynxThing: "doing sphynx stuff"
}

// this is still strings for classes
petCat({ kind: "CalicoCat", target: calico });
petCat({ kind: "SphynxCat", target: sphynx });

petCat({ kind: "Turtle", target: { appearance: "???" } });

// [LOG]: "What kind of cat am I petting?" 
// [LOG]: "Looks like a CalicoCat." 
// [LOG]: "What kind of cat am I petting?" 
// [LOG]: "Looks like a SphynxCat." 
// [LOG]: "What kind of cat am I petting?" 
// [LOG]: "This is not a Cat at all!"