add watch orphans

pkg/array/diff.go

@@ -0,0 +1,35 @@
+package array
+
+type DiffResult[T comparable] struct {
+	Added   []T
+	Removed []T
+}
+
+func Diff[T comparable](old []T, new []T) DiffResult[T] {
+	oldMap := make(map[T]struct{})
+	newMap := make(map[T]struct{})
+
+	for _, item := range old {
+		oldMap[item] = struct{}{}
+	}
+
+	for _, item := range new {
+		newMap[item] = struct{}{}
+	}
+
+	var result DiffResult[T]
+
+	for item := range newMap {
+		if _, found := oldMap[item]; !found {
+			result.Added = append(result.Added, item)
+		}
+	}
+
+	for item := range oldMap {
+		if _, found := newMap[item]; !found {
+			result.Removed = append(result.Removed, item)
+		}
+	}
+
+	return result
+}