Wrap code in function

npm-run-completion.zsh

@@ -1,5 +1,6 @@
-filename="package.json"
-dir=$PWD
+_npm_run_completion() {
+  local filename="package.json"
+  local dir=$PWD
   while [ ! -e "$dir/$filename" ]; do
     dir=${dir%/*}
     if [ "$dir" = "" ]; then
@@ -9,3 +10,4 @@ done
   if [ ! "$dir" = "" ]; then
     echo "$dir/$filename";
   fi
+}