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}`;}

[TypeScript] Distinguishing between types of Strings in TypeScript