Polymer DevTools Extenstion

[Justin Fagnani]

Greetings Polymer People!

If you don't know already, we've been developing a Polymer Chrome DevTools extension to help track performance of your elements on a fine-grained level - per tag-name and per lifecycle callback.

This extension was recently created (just the week prior to the Polymer Summit), and is still in the very earliest stages of development. Normally it wouldn't be publicized much yet, but it ended up looking like it could be very valuable to our developers, even in it's current larval form, so we published it to the Chrome Web Store, and it was briefly hinted at in some Summit talks, and has been mentioned in the Slack channel.

I wanted to take a quick moment to both let you know of its existence if you didn't already, and set some expectations at this point in time.

The extension works by hooking all custom element lifecycle callbacks, all async-related APIs in the browser, and a few Polymer async and data-binding methods. These hooks must be installed very early, before we even know that a page uses Polymer, and on every page.

As you can guess this is pretty invasive and there's the potential that the extension breaks some sites. I've already fixed breakages of GitHub and the Google homepage (positive note: web components are already more popular that we thought!).

As such, we strongly recommend that the extension is installed to a separate development-only Chrome profile. To add a new profile, use the People > Add Person... menu in Chrome. If you've installed the extension to a normal browsing profile, you can uninstall it in the chrome://extensions page.

I'd also like to add a little disclaimer about the numbers reported by the extension. We think they're correct, but due to the complexity of tracking async tasks and associating them back to the correct element, there could be some discrepancies. Of course, tackling this problem is the primary value of the extension :)

The extension has very little test coverage at the moment, and likely won't see much development for a few weeks while the Polymer team re-unites into its full Voltronic form after post-Summit travels. So... use at your own risk, and if you do use it, please report any issues.

The extension can be found on the Chrome Web Store here: https://chrome.google.com/webstore/detail/polymer-devtools-extensio/mmpfaamodhhlbadloaibpocmcomledcg

And issues can be reported here: https://github.com/PolymerLabs/polydev/issues

Thanks, and happy developing!

  Justin