updated nodejs_npm_install.sh

nodejs_npm_install.sh

@@ -30,29 +30,40 @@ usage(){
     exit 3
 }
 
-packages=""
+for arg; do
-for x in "$@"; do
+    case "$arg" in
-    if [ -f "$x" ]; then
-        echo "adding packages from file:  $x"
-        packages="$packages $(sed 's/#.*//;/^[[:space:]]*$$/d' "$x")"
-        echo
-    else
-        packages="$packages $x"
-    fi
-    packages="$(tr ' ' ' \n' <<< "$packages" | sort -u | tr '\n' ' ')"
-done
-
-for x in "$@"; do
-    case "$1" in
         -*) usage
             ;;
     esac
 done
 
+packages=""
+
+process_args(){
+    for arg; do
+        if [ -f "$arg" ]; then
+            echo "adding packages from file:  $arg"
+            packages="$packages $(sed 's/#.*//;/^[[:space:]]*$$/d' "$arg")"
+            echo
+        else
+            packages="$packages $arg"
+        fi
+    done
+}
+
+if [ -n "${*:-}" ]; then
+    process_args "$@"
+else
+    # shellcheck disable=SC2046
+    process_args $(cat)
+fi
+
 if [ -z "${packages// }" ]; then
     usage
 fi
 
+packages="$(tr ' ' ' \n' <<< "$packages" | sort -u | tr '\n' ' ')"
+
 echo "Installing NodeJS NPM packages"
 echo