An Introduction to Polymer - A Web Component Library

What I like about it most is that it lets me program for the web like I would normally code for software projects without UI. You can completely deconstruct your application into components and encapsulate logic and responsibility, giving you all the tools you need for great architecture. I am traditionally more of a backend guy, but Polymer makes building frontend projects fun for me, because the most interesting thing about programming to me is software architecture, creating powerful abstractions and designing interaction and APIs.

I have been working with Polymer since the first beta release (before 0.1) and completed multiple projects, both at work and during my free time. It has not been without it's problems. I have to say that it takes quite a while before it really 'clicked', because you have to learn quite a few patterns to make things work. If you started early on, it was very unpolished (despite that, we have a fairly large Polymer 0.5 application running in production, and it's still chugging along nicely), and the upgrade process is extremely painful (hence aforementioned application still running 0.5). It can also be dangerous, because if you don't know what you're doing, it is easy to end up with some frankenstein contraption that performs terribly, and is a horror to maintain. My advice to anyone looking to get into Polymer is to get advice from more seasoned developers, the Slack channel[1] is a great resource for that. Learn from existing projects and applications as much as possible to see how they solve the issues you will run into, and get a feeling for how the general architectural patterns work.

The good part is that all the techniques you learn are almost directly applicable to the future native Web Platform, as one of the core concepts of Polymer is that it tries to emulate what the future Web Platform will look like, and allow you to use that platform today. Quite a large part of the platform is already natively supported on most of the evergreen browsers, and I find that I use less and less Polymer code these days and use more and more plain native code. One day we may no longer use Polymer at all, but your newly learned skills will still apply.

A recent side project of mine has been an exploration of what future Web Applications might look like, and to test what is possible on the platform today. I built it completely from scratch, with no libraries or dependencies other than Polymer:

- https://overwebs.ruph.in (warning: sound and relatively high bandwidth. Works best in Chrome, other browsers untested)

[1] https://polymer-slack.herokuapp.com/

1) Very easy to learn, but it has no idiomatic way to write large applications; it is not a framework like Angular or Ember.js. What the best way is to write large, maintainable, applications with Polymer is still open IMHO.

A potentially useful way to structure large Polymer based applications is to combine Polymer and Redux, separating presentation code from state/business logic.

2) No idiomatic way to do dependency injection. In Polymer even services are stated declaratively in HTML (e.g. ``). Because of this, there is no natural way to replace my-service with, for instance, a stubbed version for testing purposes. There are some solutions, but they are somewhat laborious [1].

3) Build process still buggy. We encountered multiple issues with the polymer-vulcanize library.

Looking back at the ease with which I started writing application code using Polymer I foresee a great future for this library, especially for smaller applications. We need to learn more best practices in order to use Polymer to create large maintainable applications.

[1] “Polymer - Dependency Injection with Custom Elements by Justin Fagnani” https://www.youtube.com/watch?v=6o5zaKHedTE