4 ms·

> The implementation isn't even that horrible You're making me blush! The list of integers could be replaced by using tuples and reading their lengths to do b

• jedimastert 6y ago
  > The list of integers could be replaced by using tuples and reading their lengths to do basic arithmetic. Is that anything like church encoding? https://www.wikiwand.com/en/Church_encoding#/Church_numerals https://www.wikiwand.com/en/Church_encoding#/Church_numerals
  • jitl 6y ago
    Not really. In the Typescript type system tuple types are array types where the length is encoded in the type system. Tuple types can be “added” by concatenation to produce a new tuple type: type two = [0, 0] type three = [0, 0, 0] type five = [...two, ...three] type TupleToNumber<T extends any[]> = T[“length”] const num: TupleToNumber<five> = 5
    • akavi 6y ago
      Am I understanding this correctly that typescript provides a type-level property on tuples called `"length"`?
      • phpnode 6y ago
        yep!
      • jakear 6y ago
        To clarify, the "tuple" is just an array with fixed length. So ts isn't "providing" the length property, it's simply surfacing the underlying Array#length in JS, which it knows to be a constant.