diff --git a/lib/installPackages.js b/lib/installPackages.js
index 58abc68..79df9f4 100644
--- a/lib/installPackages.js
+++ b/lib/installPackages.js
@@ -43,10 +43,13 @@ module.exports = async ({
       args.push('--registry', registry)
     }
 
-    installArgs = args.concat(installArgs || [])
-    logger.debug(npmClient, installArgs.join(' '))
+    if (installArgs) {
+      args.push(...installArgs)
+    }
+
+    logger.debug(npmClient, args.join(' '))
     spinner.start(`Installing ${packageName} with ${npmClient}`)
-    const ps = spawn(npmClient, args.concat(installArgs || []), {
+    const ps = spawn(npmClient, args, {
       stdio: [0, 'pipe', 'pipe'],
       cwd,
       env: Object.assign(