Saturday, November 22, 2014

Polymer without Dependency Injection is dead to me

by Richard Vowles



I have been watching quite a bit of the content from the recent Chrome Dev Summit - its the only way to watch it (after the fact) because there is so much fluff in the talks. I understand why this has to be done, but appreciate that they get off the fluff and into the useful how-tos. The Service Worker stuff I am afraid to say was cleanly and clearly covered in Jake Archibald's DevBytes with the Train Spotters example, and for a feature that still isn't readily available, it seemed fairly heavily hyped. I have yet to check whether Safari will support it on iOS, but if it does I think we are going to start to be able to claw back some territory from native phone apps.

The Material Design / Web Components / Polymer focus however was more interesting - this has been going on for some time and I have been avidly following it. I like the format of web components much more than Angular Directives, I like the encapsulation of essentially everything you need. 

What I don't like however is the lack of dependency injection - even an interface for adding your own.

Whenever I see a "new XXXX' in someone's code - particularly for a service of some kind I outwardly cringe - with Angular and DI, we have been able to significantly improve the way that we build our web applications, focusing on what the customer needs and wants to see in terms of interactivity, workflow, look and feel, and just overall user experience. We attribute this not just to the superior nature of developing in Angular, but partcularly the DI capability. We can mock out our services, and even when we eventually replace them, we are still able to use them for our unit tests with Karma.

There is no such capability with +Polymer - it is listed as part of the "future roadmap" but really, it is critical. The ability to inject your actual services provides for such as well structured application.

The only workaround at the moment is to reverse it, so that every object would pull them from the global context - no Hollywood principle for us!

I would really like to use and recommend Polymer, but I simply cannot at the moment and won't be able to until I see at least some activity in this area.
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