diff --git a/narr/collection.go b/narr/collection.go
index f6d5660..50d7b3e 100644
--- a/narr/collection.go
+++ b/narr/collection.go
@@ -410,11 +410,11 @@ func ExceptWhile(data any, fn Predicate) any {
 // Map a list to new list
 //
 // eg: mapping [object0{},object1{},...] to flatten list [object0.someKey, object1.someKey, ...]
-func Map[T any, V any](list []T, mapFn func(obj T) (val V, find bool)) []V {
+func Map[T any, V any](list []T, mapFn func(idx int, obj T) (val V, find bool)) []V {
 	flatArr := make([]V, 0, len(list))
 
-	for _, obj := range list {
-		if target, ok := mapFn(obj); ok {
+	for i, obj := range list {
+		if target, ok := mapFn(i, obj); ok {
 			flatArr = append(flatArr, target)
 		}
 	}
@@ -422,17 +422,17 @@ func Map[T any, V any](list []T, mapFn func(obj T) (val V, find bool)) []V {
 }
 
 // Column alias of Map func
-func Column[T any, V any](list []T, mapFn func(obj T) (val V, find bool)) []V {
+func Column[T any, V any](list []T, mapFn func(idx int, obj T) (val V, find bool)) []V {
 	return Map(list, mapFn)
 }
 
 // Every check all true in given slice
-func Every[T any](list []T, fn func(T) bool) bool {
+func Every[T any](list []T, fn func(idx int, v T) bool) bool {
 	if len(list) == 0 {
 		return false
 	}
-	for _, t := range list {
-		if !fn(t) {
+	for i, t := range list {
+		if !fn(i, t) {
 			return false
 		}
 	}
@@ -440,12 +440,12 @@ func Every[T any](list []T, fn func(T) bool) bool {
 }
 
 // Some check some true in given slice
-func Some[T any](list []T, fn func(T) bool) bool {
+func Some[T any](list []T, fn func(idx int, v T) bool) bool {
 	if len(list) == 0 {
 		return false
 	}
-	for _, t := range list {
-		if fn(t) {
+	for i, t := range list {
+		if fn(i, t) {
 			return true
 		}
 	}
@@ -453,7 +453,7 @@ func Some[T any](list []T, fn func(T) bool) bool {
 }
 
 // Filter returns a new slice by given filter func
-func Filter[T any](list []T, filterFn func(i int, currentValue T) bool) []T {
+func Filter[T any](list []T, filterFn func(idx int, v T) bool) []T {
 	ret := make([]T, 0)
 	if list == nil {
 		return ret
@@ -469,7 +469,7 @@ func Filter[T any](list []T, filterFn func(i int, currentValue T) bool) []T {
 }
 
 // Reduce all list item by given func
-func Reduce[T any, M any](list []T, reduceFn func(total M, currentVal T, idx int) M, initialValue M) M {
+func Reduce[T any, M any](list []T, reduceFn func(sum M, v T, idx int) M, initialValue M) M {
 	ret := initialValue
 	for i, item := range list {
 		ret = reduceFn(ret, item, i)
diff --git a/narr/collection_test.go b/narr/collection_test.go
index f8b3e16..b006b96 100644
--- a/narr/collection_test.go
+++ b/narr/collection_test.go
@@ -306,7 +306,7 @@ func TestMap(t *testing.T) {
 		{"name": "john", "age": 34},
 	}
 
-	flatArr := narr.Column(list1, func(obj map[string]any) (val any, find bool) {
+	flatArr := narr.Column(list1, func(idx int, obj map[string]any) (val any, find bool) {
 		return obj["age"], true
 	})