feat: reducer, but doesn`t work

pkg/set/set.go

@@ -0,0 +1,45 @@
+package set
+
+type Set[T comparable] map[T]bool
+
+func (this *Set[T]) Add(items ...T) {
+	for _, item := range items {
+		(*this)[item] = true
+	}
+}
+
+func (this Set[T]) Has(item T) bool {
+	return this[item] == true
+}
+
+func (this *Set[T]) Remove(items ...T) {
+	for _, item := range items {
+		delete(*this, item)
+	}
+}
+
+func (this *Set[T]) Union(o Set[T]) {
+	for item := range o {
+		this.Add(item)
+	}
+}
+
+func (this Set[T]) ToList() []T {
+	list := []T{}
+
+	for item := range this {
+		list = append(list, item)
+	}
+
+	return list
+}
+
+func New[T comparable](items ...T) Set[T] {
+	result := Set[T]{}
+
+	for _, item := range items {
+		result.Add(item)
+	}
+
+	return result
+}