feat: Add MapPtr func

README.md

@@ -319,6 +319,7 @@ Type manipulation helpers:
 - [EmptyableToPtr](#emptyabletoptr)
 - [FromPtr](#fromptr)
 - [FromPtrOr](#fromptror)
+- [MapPtr](#mapptr)
 - [ToSlicePtr](#tosliceptr)
 - [FromSlicePtr](#fromsliceptr)
 - [FromSlicePtrOr](#fromsliceptror)
@@ -3646,6 +3647,18 @@ value := lo.FromPtrOr(nil, "empty")
 // "empty"
 ```
 
+### MapPtr
+
+Transforms pointer value if it's non-nil. Otherwise returns nil.
+```go
+n := 42
+value := lo.MapPtr(&n, strconv.Itoa)
+// *string{"42"}
+
+value := lo.MapPtr(nil, strconv.Itoa)
+// nil
+```
+
 ### ToSlicePtr
 
 Returns a slice of pointers to each value.

type_manipulation.go

@@ -1,6 +1,8 @@
 package lo
 
-import "reflect"
+import (
+	"reflect"
+)
 
 // IsNil checks if a value is nil or if it's a reference type with a nil underlying value.
 // Play: https://go.dev/play/p/P2sD0PMXw4F
@@ -68,6 +70,18 @@ func FromPtrOr[T any](x *T, fallback T) T {
 	return *x
 }
 
+// MapPtr transforms pointer value if it's non-nil. Otherwise returns nil.
+// Play: https://go.dev/play/p/dL7gZnzB8fX
+func MapPtr[T, R any](x *T, transform func(value T) R) *R {
+	if x == nil {
+		return nil
+	}
+
+	result := transform(*x)
+
+	return &result
+}
+
 // ToSlicePtr returns a slice of pointers to each value.
 // Play: https://go.dev/play/p/P2sD0PMXw4F
 func ToSlicePtr[T any](collection []T) []*T {

type_manipulation_test.go

@@ -1,6 +1,7 @@
 package lo
 
 import (
+	"strconv"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -134,6 +135,29 @@ func TestFromPtrOr(t *testing.T) {
 	is.Equal(fallbackInt, FromPtrOr(nil, fallbackInt))
 }
 
+func TestMapPtr(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	var (
+		fourtytwo = 42
+
+		ptr1 = &fourtytwo
+		ptr2 *int
+
+		fourtytwostring = "42"
+
+		expected1 = &fourtytwostring
+		expected2 *string
+	)
+
+	result1 := MapPtr(ptr1, strconv.Itoa)
+	result2 := MapPtr(ptr2, strconv.Itoa)
+
+	is.Equal(expected1, result1)
+	is.Equal(expected2, result2)
+}
+
 func TestToSlicePtr(t *testing.T) {
 	t.Parallel()
 	is := assert.New(t)