Add MaxIndex function

moslice/map.go

@@ -13,6 +13,19 @@ func Map[T, U any](ts []T, fn func(t T) U) (us []U) {
 	return us
 }
 
+// Map returns a new slice containing the elements of ts transformed by the passed in function.
+func MapIndex[T, U any](ts []T, fn func(t T, index int) U) (us []U) {
+	if ts == nil {
+		return nil
+	}
+
+	us = make([]U, len(ts))
+	for i, t := range ts {
+		us[i] = fn(t, i)
+	}
+	return us
+}
+
 // Map returns a new slice containing the elements of ts transformed by the passed in function, which
 // can either either a mapped value of U, or an error. If the mapping function returns an error, MapWithError
 // will return nil and the returned error.