Book Image

Progressive Web Application Development by Example

By : Chris Love
Book Image

Progressive Web Application Development by Example

By: Chris Love

Overview of this book

Are you a developer that wants to create truly cross-platform user experiences with a minimal footprint, free of store restrictions and features customers want? Then you need to get to grips with Progressive Web Applications (PWAs), a perfect amalgamation of web and mobile applications with a blazing-fast response time. Progressive Web Application Development by Example helps you explore concepts of the PWA development by enabling you to develop three projects, starting with a 2048 game. In this game, you will review parts of a web manifest file and understand how a browser uses properties to define the home screen experience. You will then move on to learning how to develop and use a podcast client and be introduced to service workers. The application will demonstrate how service workers are registered and updated. In addition to this, you will review a caching API so that you have a firm understanding of how to use the cache within a service worker, and you'll discover core caching strategies and how to code them within a service worker. Finally, you will study how to build a tickets application, wherein you’ll apply advanced service worker techniques, such as cache invalidation. Also, you'll learn about tools you can use to validate your applications and scaffold them for quality and consistency. By the end of the book, you will have walked through browser developer tools, node modules, and online tools for creating high-quality PWAs.
Table of Contents (12 chapters)

Inline critical CSS

When you inline CSS, you eliminate the required round trips to retrieve the styles, and they are immediately available to the browser as it parses the DOM. This makes these two critical steps much faster.

To refresh, when the browser encounters external style sheets, it blocks any rendering until the style sheets are fully loaded.

As I mentioned earlier, you want to limit the size of a page's CSS to just the CSS required to render the page. By limiting the styles to just those used by the page, you can typically reduce the amount of CSS to a handful of kilobytes.

Because the amount of real CSS is minimal, you can inline those styles in the document's head element. Now, the browser has no external file to download and a minimal amount of CSS to load. Plus, you have the critical styles required to render the app shell.

The PWA ticket app has a very...