Implementation of Applicative Map when Key is Monoid

[ingun37]

I need a Applicative of Map.
I know Map doesn't conform to Applicative per se but when the Key is Monoid it is possible. This is implementation of Applicative for Map in Haskell

instance (Monoid k, Ord k) => Applicative (Map k) where
  pure a = singleton mempty a
  (<*>) mkab mka =
    let f = do
            (k1, ab) <- toList mkab
            (k2, a) <- toList mka
            return (k1 `mappend` k2, ab a)
     in fromList f

I want to implement the equivalent of this piece of code using fp-ts. I tried to imitate Const's getApply while refering to How to write type class instances for your data type but I can't help feeling lost between all the HKT things 😵‍💫. Especially I feel like I have to return Applicative2C but I can't understand or find learning material about it.

Can anyone help me out doing this? I would appreciate little guide line.

[ingun37]

I think I've done it

function getApplicativeMap<K, T>(
  kMon: Monoid<K>,
  kOrd: Ord<K>
): Applicative2C<map.URI, K> {
  return {
    _E: kMon.empty,
    of(x) {
      const t = tup(kMon.empty, x);
      return pipe([t], fromTuples(kOrd));
    },
    map(fa, f) {
      return map.map(f)(fa);
    },
    URI: map.URI,
    ap(fab, fa) {
      return pipe(
        fab,
        map.toArray(kOrd),
        array.chain(([k1, ab]) =>
          pipe(
            fa,
            map.toArray(kOrd),
            array.map(([k2, a]) => tup(kMon.concat(k1, k2), ab(a)))
          )
        ),
        fromTuples(kOrd)
      );
    },
  };
}