Add EmptyableToPtr (#311)

* Add EmptyableToPtr

README.md

@@ -217,6 +217,7 @@ Conditional helpers:
 Type manipulation helpers:
 
 - [ToPtr](#toptr)
+- [EmptyableToPtr](#emptyabletoptr)
 - [FromPtr](#fromptr)
 - [FromPtrOr](#fromptror)
 - [ToSlicePtr](#tosliceptr)
@@ -2163,6 +2164,25 @@ ptr := lo.ToPtr("hello world")
 // *string{"hello world"}
 ```
 
+### EmptyableToPtr
+
+Returns a pointer copy of value if it's nonzero.
+Otherwise, returns nil pointer.
+
+```go
+ptr := lo.EmptyableToPtr[[]int](nil)
+// nil
+
+ptr := lo.EmptyableToPtr[string]("")
+// nil
+
+ptr := lo.EmptyableToPtr[[]int]([]int{})
+// *[]int{}
+
+ptr := lo.EmptyableToPtr[string]("hello world")
+// *string{"hello world"}
+```
+
 ### FromPtr
 
 Returns the pointer value or empty.

type_manipulation.go

@@ -1,10 +1,23 @@
 package lo
 
+import "reflect"
+
 // ToPtr returns a pointer copy of value.
 func ToPtr[T any](x T) *T {
 	return &x
 }
 
+// EmptyableToPtr returns a pointer copy of value if it's nonzero.
+// Otherwise, returns nil pointer.
+func EmptyableToPtr[T any](x T) *T {
+	isZero := reflect.ValueOf(&x).Elem().IsZero()
+	if isZero {
+		return nil
+	}
+
+	return &x
+}
+
 // FromPtr returns the pointer value or empty.
 func FromPtr[T any](x *T) T {
 	if x == nil {

type_manipulation_test.go

@@ -15,6 +15,24 @@ func TestToPtr(t *testing.T) {
 	is.Equal(*result1, []int{1, 2})
 }
 
+func TestEmptyableToPtr(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	is.Nil(EmptyableToPtr(0))
+	is.Nil(EmptyableToPtr(""))
+	is.Nil(EmptyableToPtr[[]int](nil))
+	is.Nil(EmptyableToPtr[map[int]int](nil))
+	is.Nil(EmptyableToPtr[error](nil))
+
+	is.Equal(*EmptyableToPtr(42), 42)
+	is.Equal(*EmptyableToPtr("nonempty"), "nonempty")
+	is.Equal(*EmptyableToPtr([]int{}), []int{})
+	is.Equal(*EmptyableToPtr([]int{1, 2}), []int{1, 2})
+	is.Equal(*EmptyableToPtr(map[int]int{}), map[int]int{})
+	is.Equal(*EmptyableToPtr(assert.AnError), assert.AnError)
+}
+
 func TestFromPtr(t *testing.T) {
 	t.Parallel()
 	is := assert.New(t)