[TypeScript] Distinguishing between types of Strings in TypeScript

In JavaScript, many libraries use string arguments to change behavior. In this lesson we learn how Typescript catches string related errors at compile time by assigning a string literal as a type.

type whiteList = "DOG" | "CAT" | "BIRD";
function allowToTake(num: number, animal: whiteList): string{
  return `You can bring ${num} ${animal}`;
}