diff --git a/npm-run-completion.zsh b/npm-run-completion.zsh
index 6a3bef2..1740c32 100644
--- a/npm-run-completion.zsh
+++ b/npm-run-completion.zsh
@@ -1,11 +1,13 @@
-filename="package.json"
-dir=$PWD
-while [ ! -e "$dir/$filename" ]; do
-  dir=${dir%/*}
-  if [ "$dir" = "" ]; then
-    break;
+_npm_run_completion() {
+  local filename="package.json"
+  local dir=$PWD
+  while [ ! -e "$dir/$filename" ]; do
+    dir=${dir%/*}
+    if [ "$dir" = "" ]; then
+        break;
+      fi
+  done
+  if [ ! "$dir" = "" ]; then
+    echo "$dir/$filename";
   fi
-done
-if [ ! "$dir" = "" ]; then
-  echo "$dir/$filename";
-fi
+}