From e84fd344646e6ca35d17942d9cac399ad695318e Mon Sep 17 00:00:00 2001
From: esafonov <esafonov@ozon.ru>
Date: Sun, 3 Dec 2023 12:41:27 +0700
Subject: [PATCH] ptr.Coalesce

---
 ptr/ptr.go      | 10 ++++++++++
 ptr/ptr_test.go | 15 +++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/ptr/ptr.go b/ptr/ptr.go
index 409c596..052090c 100644
--- a/ptr/ptr.go
+++ b/ptr/ptr.go
@@ -106,3 +106,13 @@ func StrDef[T any](v *T, def string) string {
 	}
 	return fmt.Sprintf("%v", *v)
 }
+
+// Coalesce returns first not nil. If all elements are nil, nil will be returned.
+func Coalesce[T any](pp ...*T) *T {
+	for _, p := range pp {
+		if p != nil {
+			return p
+		}
+	}
+	return nil
+}
diff --git a/ptr/ptr_test.go b/ptr/ptr_test.go
index c057e9f..2d4a6c1 100644
--- a/ptr/ptr_test.go
+++ b/ptr/ptr_test.go
@@ -44,3 +44,18 @@ func ExampleEqual() {
 	// true
 	// false
 }
+
+func ExampleCoalesce() {
+	fmt.Println(Value(Coalesce[int](nil, Of(1), Of(2))))
+	fmt.Println(Value(Coalesce[int](Of(2), Of(1), nil)))
+	fmt.Println(Value(Coalesce[int](Of(2))))
+	fmt.Println(Coalesce[int](nil, nil))
+	fmt.Println(Coalesce[int]())
+
+	// Output:
+	// 1
+	// 2
+	// 2
+	// <nil>
+	// <nil>
+}