tpl/collections: Improve type handling in collections.Slice

Fixes #5188

1 files changed, 7 insertions, 0 deletions

diff --git a/common/collections/collections.go b/common/collections/collections.go
index bb47c8acc..854f705b3 100644
--- a/common/collections/collections.go
+++ b/common/collections/collections.go
@@ -19,3 +19,10 @@ package collections
 type Grouper interface {
 	Group(key interface{}, items interface{}) (interface{}, error)
 }
+
+// Slicer definse a very generic way to create a typed slice. This is used
+// in collections.Slice template func to get types such as Pages, PageGroups etc.
+// instead of the less useful []interface{}.
+type Slicer interface {
+	Slice(items []interface{}) (interface{}, error)
+}