From 06a37f37b7bf58f3630babd9701bc1b43da1292a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mike=20Schw=C3=B6rer?= <pubgit@mikescher.com>
Date: Sat, 19 Nov 2022 16:26:45 +0100
Subject: [PATCH] v0.0.20

---
 dataext/merge.go      | 35 ++++++++++++++++++++++
 dataext/merge_test.go | 70 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 dataext/merge.go
 create mode 100644 dataext/merge_test.go

diff --git a/dataext/merge.go b/dataext/merge.go
new file mode 100644
index 0000000..0ad5156
--- /dev/null
+++ b/dataext/merge.go
@@ -0,0 +1,35 @@
+package dataext
+
+import (
+	"reflect"
+)
+
+func ObjectMerge[T1 any, T2 any](base T1, override T2) T1 {
+
+	reflBase := reflect.ValueOf(&base).Elem()
+	reflOvrd := reflect.ValueOf(&override).Elem()
+
+	for i := 0; i < reflBase.NumField(); i++ {
+
+		fieldBase := reflBase.Field(i)
+		fieldOvrd := reflOvrd.Field(i)
+
+		if fieldBase.Kind() != reflect.Ptr || fieldOvrd.Kind() != reflect.Ptr {
+			continue
+		}
+
+		kindBase := fieldBase.Type().Elem().Kind()
+		kindOvrd := fieldOvrd.Type().Elem().Kind()
+
+		if kindBase != kindOvrd {
+			continue
+		}
+
+		if !fieldOvrd.IsNil() {
+			fieldBase.Set(fieldOvrd.Elem().Addr())
+		}
+
+	}
+
+	return base
+}
diff --git a/dataext/merge_test.go b/dataext/merge_test.go
new file mode 100644
index 0000000..f5b1031
--- /dev/null
+++ b/dataext/merge_test.go
@@ -0,0 +1,70 @@
+package dataext
+
+import (
+	"gogs.mikescher.com/BlackForestBytes/goext/langext"
+	"testing"
+)
+
+func TestObjectMerge(t *testing.T) {
+	type A struct {
+		Field1   *int
+		Field2   *string
+		Field3   *float64
+		Field4   *bool
+		OnlyA    int64
+		DiffType int
+	}
+	type B struct {
+		Field1   *int
+		Field2   *string
+		Field3   *float64
+		Field4   *bool
+		OnlyB    int64
+		DiffType string
+	}
+
+	valueA := A{
+		Field1:   nil,
+		Field2:   langext.Ptr("99"),
+		Field3:   langext.Ptr(12.2),
+		Field4:   nil,
+		OnlyA:    1,
+		DiffType: 2,
+	}
+
+	valueB := B{
+		Field1:   langext.Ptr(12),
+		Field2:   nil,
+		Field3:   langext.Ptr(13.2),
+		Field4:   nil,
+		OnlyB:    1,
+		DiffType: "X",
+	}
+
+	valueMerge := ObjectMerge(valueA, valueB)
+
+	assertPtrEqual(t, "Field1", valueMerge.Field1, valueB.Field1)
+	assertPtrEqual(t, "Field2", valueMerge.Field2, valueA.Field2)
+	assertPtrEqual(t, "Field3", valueMerge.Field3, valueB.Field3)
+	assertPtrEqual(t, "Field4", valueMerge.Field4, nil)
+
+}
+
+func assertPtrEqual[T1 comparable](t *testing.T, ident string, actual *T1, expected *T1) {
+	if actual == nil && expected == nil {
+		return
+	}
+	if actual != nil && expected != nil {
+		if *actual != *expected {
+			t.Errorf("[%s] values differ: Actual: '%v', Expected: '%v'", ident, *actual, *expected)
+		} else {
+			return
+		}
+	}
+	if actual == nil && expected != nil {
+		t.Errorf("[%s] values differ: Actual: nil, Expected: not-nil", ident)
+	}
+	if actual != nil && expected == nil {
+		t.Errorf("[%s] values differ: Actual: not-nil, Expected: nil", ident)
+	}
+}