diff --git a/docs/tutorial/quick-start.md b/docs/tutorial/quick-start.md
index 4c61413436dd..bc1a0f69e353 100644
--- a/docs/tutorial/quick-start.md
+++ b/docs/tutorial/quick-start.md
@@ -78,6 +78,8 @@ The `main.js` should create windows and handle system events, a typical
 example being:
 
 ```javascript
+'use strict';
+
 const electron = require('electron');
 const app = electron.app;  // Module to control application life.
 const BrowserWindow = electron.BrowserWindow;  // Module to create native browser window.