Learn the fundamentals necessary to build custom JavaScript components. Ideal for JavaScript developers with little experience using component libraries, as well as front-end engineers with significant component library experience who want to create their own custom components, this book takes you through the development of an example component from conceptualization, design, and implementation. The latter half of the book covers encapsulation, packaging, and deployment.Start with the basics and move progressively toward creating your own functioning componentsLook under the hood, and learn about the shadow DOM, imports, custom elements, and other topicsEncapsulate, package, and deploy your componentsLearn how to use Polymer and Bower to package and deploy your web components
The book is pretty outdated. Most APIs referenced in the book have been deprecated or never made into the HTML spec. A lot of the book is about jQuery or Polymer and not about Web Components.
Though not perfect, I'd recommend Web Components in action as an alternative.
A book about Web Components where Polymer gets introduced around 75%. Weird :)
But it's not as bad as it seems, author is very thorough in presenting the need for componentization, problems you'll encounter & ways to achieve the target. If you know Backbone.js, it may be a bit boring and slow (part II, OMG ...), but things start to get interesting when author introduces Shadow DOM & Custom Elements.
What's more? Polymer chapter is a bit dated (0.5) & the testing part is very brief (but at least Karma got some love). Code samples are really nice (in whole book).