A good foundation is critical, so you will learn how to create a useful workflow to make development easier. From there, the next version of JavaScript (ES6) and the CSS pre-processor SASS are introduced as a way to simplify creating the look of the mobile application. Responsive design techniques are also covered, including the flexbox layout module. As many apps are data-driven, you'll build an application throughout the course of the book that relies upon IndexedDB and SQLite. You'll also download additional content and address how to handle in-app purchases. Furthermore, you'll build your own customized plugins for your particular use case. When the app is complete, the book will guide you through the steps necessary to submit your app to the Google Play and Apple iTunes stores.