diff --git a/helper/map.go b/helper/map.go
index fc4330f..d54b198 100644
--- a/helper/map.go
+++ b/helper/map.go
@@ -50,38 +50,36 @@ func MapValuesFunc[M ~map[K]V, T any, K comparable, V any](maps M, convert func(
 	return values
 }
 
+func ToMapWithIndex[S ~[]E, K comparable, V, E any](s S, convert func(int, E) (K, V)) map[K]V {
+	_len := len(s)
+	maps := make(map[K]V, _len)
+	for i := 0; i < _len; i++ {
+		k, v := convert(i, s[i])
+		maps[k] = v
+	}
+	return maps
+}
+
+func ToMap[S ~[]E, K comparable, V, E any](s S, convert func(E) (K, V)) map[K]V {
+	return ToMapWithIndex(s, func(_ int, e E) (K, V) { return convert(e) })
+}
+
 // ToSetMap converts a slice s to a set map.
 func ToSetMap[S ~[]T, T comparable](s S) map[T]struct{} {
-	m := make(map[T]struct{}, len(s))
-	for _, k := range s {
-		m[k] = struct{}{}
-	}
-	return m
+	return ToMap(s, func(e T) (T, struct{}) { return e, struct{}{} })
 }
 
 // ToBoolMap converts a slice s to a bool map.
 func ToBoolMap[S ~[]T, T comparable](s S) map[T]bool {
-	m := make(map[T]bool, len(s))
-	for _, k := range s {
-		m[k] = true
-	}
-	return m
+	return ToMap(s, func(e T) (T, bool) { return e, true })
 }
 
 // ToSetMapFunc converts a slice s to a set map by a conversion function.
 func ToSetMapFunc[S ~[]T, K comparable, T any](s S, convert func(T) K) map[K]struct{} {
-	m := make(map[K]struct{}, len(s))
-	for _, k := range s {
-		m[convert(k)] = struct{}{}
-	}
-	return m
+	return ToMap(s, func(e T) (K, struct{}) { return convert(e), struct{}{} })
 }
 
 // ToBoolMapFunc converts a slice s to a bool map by a conversion function.
 func ToBoolMapFunc[S ~[]T, K comparable, T any](s S, convert func(T) K) map[K]bool {
-	m := make(map[K]bool, len(s))
-	for _, k := range s {
-		m[convert(k)] = true
-	}
-	return m
+	return ToMap(s, func(e T) (K, bool) { return convert(e), true })
 }