Unknown in TypeScript

let x: unknown;

x = 12;

if (typeof x === "number") {
  x += 100;
}

x = "Horse";

if (typeof x === "string") {
  console.log(x.length);
}

class Monkey {
  constructor(public name: string) {}
}

x = new Monkey("George");

let demeanor = "";

if (x instanceof Monkey) {
  demeanor = "Curious";
} else {
  demeanor = "Do not know";
}

// Good Example Here https://mariusschulz.com/blog/the-unknown-type-in-typescript#example-reading-json-from-localstorage