minidom: fix insertText if before is first in parent

1 files changed, 5 insertions, 1 deletions

diff --git a/chame/minidom.nim b/chame/minidom.nim
index 5e6f0938..717f4b59 100644
--- a/chame/minidom.nim
+++ b/chame/minidom.nim
@@ -166,7 +166,11 @@ proc insertBefore(builder: DOMBuilder[Node], parent, child, before: Node) =
 proc insertText(builder: DOMBuilder[Node], parent: Node, text: string,
     before: Node) =
   let prevSibling = if before != nil:
-    parent.childList[parent.childList.find(before) - 1]
+    let i = parent.childList.find(before)
+    if i == 0:
+      nil
+    else:
+      parent.childList[i - 1]
   elif parent.childList.len > 0:
     parent.childList[^1]
   else: