1 files changed, 34 insertions, 0 deletions
diff --git a/filter.go b/filter.go
new file mode 100644
index 0000000..20c23a9
--- /dev/null
+++ b/filter.go
@@ -0,0 +1,34 @@
+package collection
+
+import "sync"
+
+func FilterSync[T any](collection []T, filter func(item T, idx int) bool) []T {
+	var result []T
+	for i, v := range collection {
+		if filter(v, i) {
+			result = append(result, v)
+		}
+	}
+	return result
+}
+
+func Filter[T any](collection []T, filter func(item T, idx int) bool) []T {
+	var result []T
+	mu := sync.Mutex{}
+	wg := sync.WaitGroup{}
+	wg.Add(len(collection))
+	for i, v := range collection {
+		func(v T, i int) {
+			go func() {
+				defer wg.Done()
+				if filter(v, i) {
+					mu.Lock()
+					result = append(result, v)
+					mu.Unlock()
+				}
+			}()
+		}(v, i)
+	}
+	wg.Wait()
+	return result
+}