BFE.devでのAI解答例 - TypeScript タイプパズル
52. implement Split<S, D>

type Split<S extends string, D extends string> = S extends `${infer L}${D}${infer R}`  ? [L, ...Split<R, D>]  : [S];

Explanation:

• We start by defining a generic type Split<S, D> where S is the input string and D is the delimiter to split the string with.
• We use conditional type checking to check if the input string contains the delimiter. If it does, we split the string into two parts, separated by the delimiter. We use the infer keyword to extract the first part of the string, denoted by L.
• We then recursively call Split<R, D> on the second part of the string, denoted by R. We use the spread operator ... to concatenate L and the result of the recursive Split call.
• If the input string does not contain the delimiter, we simply return an array with the input string as the only element.

Note: We could have also used string instead of S and D to allow for any string input, but using generics provides better type safety.