What does the following type produce and how does it work? type Zip = T extends [infer TH, …infer TT] ? U extends [infer UH, …infer UT] ? [[TH, UH], …Zip] : [] : [];

Question

TypeScript Professional — Hard

What does the following type produce and how does it work? type Zip = T extends [infer TH, …infer TT] ? U extends [infer UH, …infer UT] ? [[TH, UH], …Zip] : [] : [];

Accepted Answer

The type Zip creates a tuple of paired elements from T and U, similar to Python's zip function. It stops at the shorter tuple and is fully resolved at the type level.