RWILT #1

by doubledebug

HTML

<p id="p1">Test 1: </p>
<p id="p2">Test 2: </p>

TypeScript

type User = {
  name: string;
  age: number;
}

function formatUsername(user: User) {
  return `${user.name}, ${user.age}`;
}

const user1 = { name: 'Dule', age: 25}
const user2 = { name: null }

document.getElementById('p1').textContent += formatUsername(user1); // ✔️
document.getElementById('p2').textContent += formatUsername(user2); // ✔️ error at compile time