// Convert all properties to boolean type Flags<T> = { [K in keyof T]: boolean; }; interface User { id: number; name: string; email: string; } const user: User = { id: 1, name: "Alice", email: "alice@example.com" }; function createFlags<T extends object>(obj: T): Flags<T> { const out: any = {}; for (const k in obj) out[k] = true; return out; } const userFlags = createFlags(user); console.log(userFlags.id); console.log(userFlags.name); console.log(userFlags.email);