message: use pipeable
diff: @@ -76,14 +76,16 @@ describe("HashMap", () => {
  [new Index(3, 3), 6]
  ])
  expect(
  - Array.from(
  - HM.chainWithIndex_(map, (k, v) =>
  + pipe(
  + map,
  + HM.chainWithIndex((k, v) =>
  pipe(
  makeMap(),
  HM.set(new Index(k.a + 1, k.b + 1), new Value(v.c, v.d + 1)),
  HM.set(new Index(k.a + 6, k.b + 6), new Value(v.c + 1, v.d + 1))
  )
  - )
  + ),
  + Array.from
  )
  ).toEqual([
  [new Index(8, 8), new Value(6, 6)],
  