feat: add AddIfNotExistBy function for set

datastructure/set/set.go

@@ -4,19 +4,47 @@ package datastructure
 type Set[T comparable] map[T]struct{}
 
 // NewSet return a instance of set
-func NewSet[T comparable](values ...T) Set[T] {
+func NewSet[T comparable](items ...T) Set[T] {
 	set := make(Set[T])
-	set.Add(values...)
+	set.Add(items...)
 	return set
 }
 
-// Add value to set
-func (s Set[T]) Add(values ...T) {
-	for _, v := range values {
+// Add items to set
+func (s Set[T]) Add(items ...T) {
+	for _, v := range items {
 		s[v] = struct{}{}
 	}
 }
 
+// AddIfNotExist checks if item exists in the set,
+// it adds the item to set and returns true if it does not exist in the set,
+// or else it does nothing and returns false.
+func (s Set[T]) AddIfNotExist(value T) bool {
+	if !s.Contain(value) {
+		if _, ok := s[value]; !ok {
+			s[value] = struct{}{}
+			return true
+		}
+	}
+	return false
+}
+
+// AddIfNotExistBy checks if item exists in the set and pass the `checker` function
+// it adds the item to set and returns true if it does not exists in the set and
+// function `checker` returns true, or else it does nothing and returns false.
+func (s Set[T]) AddIfNotExistBy(item T, checker func(element T) bool) bool {
+	if !s.Contain(item) {
+		if checker(item) {
+			if _, ok := s[item]; !ok {
+				s[item] = struct{}{}
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // Contain checks if set contains value or not
 func (s Set[T]) Contain(value T) bool {
 	_, ok := s[value]
@@ -41,9 +69,9 @@ func (s Set[T]) Clone() Set[T] {
 	return set
 }
 
-// Delete value of set
-func (s Set[T]) Delete(values ...T) {
-	for _, v := range values {
+// Delete item of set
+func (s Set[T]) Delete(items ...T) {
+	for _, v := range items {
 		delete(s, v)
 	}
 }
@@ -76,13 +104,13 @@ func (s Set[T]) Size() int {
 
 // Values return all values of set
 func (s Set[T]) Values() []T {
-	values := make([]T, 0, 0)
+	result := make([]T, 0, len(s))
 
 	s.Iterate(func(value T) {
-		values = append(values, value)
+		result = append(result, value)
 	})
 
-	return values
+	return result
 }
 
 // Union creates a new set contain all element of set s and other

datastructure/set/set_test.go

@@ -17,6 +17,38 @@ func TestSet_Add(t *testing.T) {
 	assert.Equal(true, set.Equal(expected))
 }
 
+func TestSet_AddIfNotExist(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSet_AddIfNotExist")
+
+	set := NewSet[int]()
+	set.Add(1, 2, 3)
+
+	assert.Equal(false, set.AddIfNotExist(1))
+	assert.Equal(true, set.AddIfNotExist(4))
+	assert.Equal(NewSet(1, 2, 3, 4), set)
+}
+
+func TestSet_AddIfNotExistBy(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSet_AddIfNotExistBy")
+
+	set := NewSet[int]()
+	set.Add(1, 2)
+
+	ok := set.AddIfNotExistBy(3, func(val int) bool {
+		return val%2 != 0
+	})
+
+	notOk := set.AddIfNotExistBy(4, func(val int) bool {
+		return val%2 != 0
+	})
+
+	assert.Equal(true, ok)
+	assert.Equal(false, notOk)
+
+	assert.Equal(true, set.Contain(3))
+	assert.Equal(false, set.Contain(4))
+}
+
 func TestSet_Contain(t *testing.T) {
 	assert := internal.NewAssert(t, "TestSet_Contain")