diff --git a/README.md b/README.md
index 6423bf7..9df4975 100644
--- a/README.md
+++ b/README.md
@@ -400,15 +400,15 @@ func DeleteByIndex(slice interface{}, start int, end ...int) (interface{}, error
 func Drop(slice interface{}, n int) interface{} //creates a slice with `n` elements dropped from the beginning when n > 0, or `n` elements dropped from the ending when n < 0
 func Every(slice, function interface{}) bool //return true if all of the values in the slice pass the predicate function, function signature should be func(index int, value interface{}) bool
 func None(slice, function interface{}) bool // return true if all the values in the slice mismatch the criteria
-func Filter(slice, function interface{}) interface{} //filter slice, function signature should be func(index int, value interface{}) bool
+func Filter [T any] (slice []T, fn func(index int, t T) bool) []T //filter slice, fn signature should be func(int, T) bool.
 func Find(slice, function interface{}) (interface{}, bool) //iterates over elements of slice, returning the first one that passes a truth test on function.function signature should be func(index int, value interface{}) bool .
 func FlattenDeep(slice interface{}) interface{} //flattens slice recursive
-func ForEach(slice, function interface{}) //iterates over elements of slice and invokes function for each element, function signature should be func(index int, value interface{}) 
+func ForEach [T any] (slice []T, fn func(index int, t T)) //iterates over elements of slice and invokes function for each element, fn signature should be func(int, T ).
 func IntSlice(slice interface{}) ([]int, error) //convert value to int slice
 func InterfaceSlice(slice interface{}) []interface{} //convert value to interface{} slice
 func Intersection(slices ...interface{}) interface{} //creates a slice of unique values that included by all slices.
 func InsertByIndex(slice interface{}, index int, value interface{}) (interface{}, error) //insert the element into slice at index.
-func Map(slice, function interface{}) interface{} //map lisce, function signature should be func(index int, value interface{}) interface{}
+func Map [T any, U any] (slice []T, fn func(index int, t T) U) []U //map lisce, fn signature should be func(int, T).
 func ReverseSlice(slice interface{}) //revere slice
 func Reduce(slice, function, zero interface{}) interface{} //reduce slice, function signature should be func(index int, value1, value2 interface{}) interface{}
 func Shuffle(slice interface{}) interface{} //creates an slice of shuffled values
diff --git a/slice/slice.go b/slice/slice.go
index 39a61c6..7a1f38d 100644
--- a/slice/slice.go
+++ b/slice/slice.go
@@ -167,7 +167,7 @@ func Some(slice, function interface{}) bool {
 
 // Filter iterates over elements of slice, returning an slice of all elements `signature` returns truthy for.
 // The fn signature should be func(int, T) bool.
-func Filter[T any](slice []T, fn func(index int, t T) bool) []T {
+func Filter [T any] (slice []T, fn func(index int, t T) bool) []T {
 	res := make([]T, 0, 0)
 	for i, v := range slice {
 		if fn(i, v) {
@@ -279,7 +279,7 @@ func flattenRecursive(value reflect.Value, result reflect.Value) reflect.Value {
 
 // ForEach iterates over elements of slice and invokes function for each element
 // The fn signature should be func(int, T ).
-func ForEach[T any] (slice []T, fn func(index int, t T)) {
+func ForEach [T any] (slice []T, fn func(index int, t T)) {
 	for i, v := range slice {
 		fn(i, v)
 	}
@@ -287,7 +287,7 @@ func ForEach[T any] (slice []T, fn func(index int, t T)) {
 
 // Map creates an slice of values by running each element of `slice` thru `function`.
 // The fn signature should be func(int, T).
-func Map[T any, U any](slice []T, fn func(index int, t T) U) []U {
+func Map [T any, U any] (slice []T, fn func(index int, t T) U) []U {
 	res := make([]U, len(slice), cap(slice))
 	for i, v := range slice {
 		res[i] = fn(i, v)