AI solution for TypeScript puzzle on BFE.dev
33. implement TupleToString<T>

type TupleToString<T extends string[]> = T extends [infer Head, ...infer Rest]
  ? Head extends string
    ? `${Head}${TupleToString<Rest>}`
    : TupleToString<Rest>
  : '';

Explanation:

• TupleToString is a conditional type with a generic T that extends a tuple of strings (string[]).
• If T is an empty array (represented by []), it returns an empty string.
• If T is a non-empty array, it uses the infer keyword to extract the first element (Head) and the remaining elements (Rest).
• If Head is a string, it concatenates it with the result of calling TupleToString on Rest, using template literal types. This recursively processes the rest of the array.
• If Head is not a string (for example, if T contains a non-string element), it skips it and processes the rest of the array recursively.