TypeScript Fundamentals With AI

// Always start with strict mode in tsconfig.json
// { "compilerOptions": { "strict": true, "target": "ES2022" } }

function greet(name: string, loud = false): string {
  const msg = `Hello, ${name}!`;
  return loud ? msg.toUpperCase() : msg;
}

console.log(greet("Ada"));
console.log(greet("Bo", true));
// greet(42); // compile error: number is not string

type Status = "idle" | "loading" | "error" | "success";

function label(s: Status): string {
  switch (s) {
    case "idle":    return "Ready";
    case "loading": return "Working...";
    case "error":   return "Try again";
    case "success": return "Done";
  }
}