foldMap<B> method
Fold implemented by mapping A
values into B
and then
combining them using the given Monoid<B>
instance.
Use Monoid<B>
to provide the initial value of the fold (empty
) and
the combine
function to combine the accumulator B
with the value of
type B
computed using the function f
from type A
(f(a)
).
Implementation
B foldMap<B>(Monoid<B> monoid, B Function(A a) f) =>
foldRight(monoid.empty, (b, a) => monoid.combine(f(a), b));