From 49da23ca5f4fb321552f69a5cb4517bcf6941ed6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rados=C5=82aw=20Str=C4=85czy=C5=84ski?=
 <radoslaw.straczynski@msales.com>
Date: Tue, 1 Jun 2021 09:34:31 +0200
Subject: [PATCH] Slice filtering fix. (#15)

---
 slicex/slice.go      |  2 +-
 slicex/slice_test.go | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/slicex/slice.go b/slicex/slice.go
index e3f2d9c..d24db0a 100644
--- a/slicex/slice.go
+++ b/slicex/slice.go
@@ -25,7 +25,7 @@ func Filter(x interface{}, filter func(i int) bool) {
 	v := ptr.Elem()
 	validateReflection("Filter", reflect.Slice, v)
 
-	for i := 0; i < v.Len(); i++ {
+	for i := v.Len() - 1; i >= 0; i-- {
 		if filter(i) {
 			v.Set(reflect.AppendSlice(v.Slice(0, i), v.Slice(i+1, v.Len())))
 		}
diff --git a/slicex/slice_test.go b/slicex/slice_test.go
index 2de7b43..d486ff4 100644
--- a/slicex/slice_test.go
+++ b/slicex/slice_test.go
@@ -111,6 +111,17 @@ func TestFilterInt_Filtered(t *testing.T) {
 	}
 }
 
+func TestFilterInt_AllFiltered(t *testing.T) {
+	slice := []int{2, 4, 6, 8}
+	want := []int{}
+	Filter(&slice, func(i int) bool {
+		return slice[i]%2 == 0
+	})
+	if !reflect.DeepEqual(want, slice) {
+		t.Errorf("Got %+v, want %+v", slice, want)
+	}
+}
+
 func TestFilterInt_NotFiltered(t *testing.T) {
 	slice := []int{1, 2, 3}
 	want := []int{1, 2, 3}