AI solution for TypeScript puzzle on BFE.dev
48. implement Divide<A, B>

Here is one possible solution:

type Divide<A extends number, B extends number> = 
  B extends 0 ? never :
  A extends 0 ? 0 :
  A extends B ? 1 :
  A extends B ? 1 :
  A extends infer X ? B extends infer Y ?
    number extends X | Y ? never :
    _Divide<0, A, B> extends infer R ? R :
    never :
    never;

type _Divide<C extends number, A extends number, B extends number> =
  A extends 0 ? C :
  B extends 1 ? A - C :
  _Divide<C | B, A - B, B>;

The Divide type takes two number parameters A and B, and returns the result of dividing A by B (rounded down to the nearest integer). To handle the edge cases of dividing by 0 or 1, we use conditional types to return never or 0 respectively. Otherwise, we call a helper type _Divide which does the actual division by repeatedly subtracting B from A until A becomes less than B. The current quotient C is accumulated by adding B to C at each step, until A reaches 0. Finally, the result is returned as C.

Note that this solution relies on the fact that TypeScript supports recursive conditional types, which allow us to define types that depend on their own type parameters. This feature was added in TypeScript 4.1.