diff --git a/to.go b/to.go
index d27dff7..f4a65ca 100644
--- a/to.go
+++ b/to.go
@@ -30,23 +30,18 @@ func ToList[T any](ch <-chan T) *list.List {
 }
 
 // ToMap returns a map containing all values read from ch.
-// The map keys are determined by f
-func ToMap[K comparable, V any](ch <-chan V, f func(V) K) map[K]V {
+// The map key-value pairs are determined by f
+func ToMap[T any, K comparable, V any](ch <-chan T, f func(T) (K, V)) map[K]V {
 	m := map[K]V{}
-	Each(ch, func(value V) { m[f(value)] = value })
-	return m
-}
-
-// ToKeyMap returns a map containing all values read from ch as keys.
-// The map values are determined by f
-func ToKeyMap[K comparable, V any](ch <-chan K, f func(K) V) map[K]V {
-	m := map[K]V{}
-	Each(ch, func(key K) { m[key] = f(key) })
+	Each(ch, func(value T) {
+		k, v := f(value)
+		m[k] = v
+	})
 	return m
 }
 
 // ToStructMap returns a struct{} map containing all values read from ch as keys.
-// It is a shorthand for ToKeyMap(ch, func(k K) struct{} { return struct{}{} })
+// It is a shorthand for ToMap(ch, func(value T) (T, struct{}) { return value, struct{}{} })
 func ToStructMap[T comparable](ch <-chan T) map[T]struct{} {
-	return ToKeyMap(ch, func(key T) struct{} { return struct{}{} })
+	return ToMap(ch, func(value T) (T, struct{}) { return value, struct{}{} })
 }