These five questions show up in almost every TypeScript interview. They're not tricky syntax puzzles. They test whether you understand the type system well enough to use it on purpose instead of just making the compiler happy.
any vs unknown
any turns type checking off. Once a value is any, TypeScript stops protecting you and mistakes slip through until runtime. unknown is the safe counterpart: it can hold anything, but you must narrow it before using it.
const a: any = "hello";
a.toUpperCase(); // ✅ no error
