union package:mono-traversable
Get the union of two containers.
Combine two maps.
When a key exists in both maps, apply a function to both of the values
and use the result of that as the value of the key in the resulting
map.
Combine a collection of SetContainers, with left-most values
overriding when there are matching keys.
Combine a list of maps.
When a key exists in two different maps, apply a function to both of
the values and use the result of that as the value of the key in the
resulting map.