From 82902877934be3638f4f74f038145a88de72e22b Mon Sep 17 00:00:00 2001
From: Corentin Clabaut <7072139+CorentinClabaut@users.noreply.github.com>
Date: Sun, 24 Jul 2022 21:35:10 +0200
Subject: [PATCH] Add FromPtrOr (#177)

---
 README.md                 | 14 ++++++++++++++
 type_manipulation.go      |  9 +++++++++
 type_manipulation_test.go | 17 +++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/README.md b/README.md
index bc92360a..50997b8d 100644
--- a/README.md
+++ b/README.md
@@ -176,6 +176,7 @@ Type manipulation helpers:
 
 - [ToPtr](#toptr)
 - [FromPtr](#fromptr)
+- [FromPtrOr](#fromptror)
 - [ToSlicePtr](#tosliceptr)
 - [ToAnySlice](#toanyslice)
 - [FromAnySlice](#fromanyslice)
@@ -1519,6 +1520,19 @@ value := lo.FromPtr[string](nil)
 // ""
 ```
 
+### FromPtrOr
+
+Returns the pointer value or the fallback value.
+
+```go
+str := "hello world"
+value := lo.FromPtrOr[string](&str, "empty")
+// "hello world"
+
+value := lo.FromPtrOr[string](nil, "empty")
+// "empty"
+```
+
 ### ToSlicePtr
 
 Returns a slice of pointer copy of value.
diff --git a/type_manipulation.go b/type_manipulation.go
index 118609b2..fe99ee1f 100644
--- a/type_manipulation.go
+++ b/type_manipulation.go
@@ -14,6 +14,15 @@ func FromPtr[T any](x *T) T {
 	return *x
 }
 
+// FromPtrOr returns the pointer value or the fallback value.
+func FromPtrOr[T any](x *T, fallback T) T {
+	if x == nil {
+		return fallback
+	}
+
+	return *x
+}
+
 // ToSlicePtr returns a slice of pointer copy of value.
 func ToSlicePtr[T any](collection []T) []*T {
 	return Map(collection, func(x T, _ int) *T {
diff --git a/type_manipulation_test.go b/type_manipulation_test.go
index 67dc94a6..c5553ed2 100644
--- a/type_manipulation_test.go
+++ b/type_manipulation_test.go
@@ -27,6 +27,23 @@ func TestFromPtr(t *testing.T) {
 	is.EqualValues(ptr, FromPtr(&ptr))
 }
 
+func TestFromPtrOr(t *testing.T) {
+	is := assert.New(t)
+
+	const fallbackStr = "fallback"
+	str := "foo"
+	ptrStr := &str
+
+	const fallbackInt = -1
+	i := 9
+	ptrInt := &i
+
+	is.Equal(str, FromPtrOr(ptrStr, fallbackStr))
+	is.Equal(fallbackStr, FromPtrOr(nil, fallbackStr))
+	is.Equal(i, FromPtrOr(ptrInt, fallbackInt))
+	is.Equal(fallbackInt, FromPtrOr(nil, fallbackInt))
+}
+
 func TestToSlicePtr(t *testing.T) {
 	is := assert.New(t)