Re: W3C Polyfill service?

Alex:
> I'm not sure the W3C is really suited to the task of running
web-critical, high-performance infrastructure.

Agreed. The angle that intrigued me was the idea of the W3C 'blessing'
(though co-branding, use of a w3.org subdomain, governance etc) a single
co-ordinated polyfill effort, but without taking on the responsibility for
the infrastructure.  Currently Fastly and Heroku run the infrastructure for
polyfill.io and they seem well suited to it.

Travis:
> What would be the goal of a polyfil repository? Would they count as an
implementation of a feature? Could they also be used to help the testing
effort? If so, then I would love to see them integrated into
web-platform-tests

Goals are to enable faster adoption of new platform features.  Developers
can be hesitant if they think the polyfill will bloat their code, or if
they are not sure if it's any good, etc.  Web platform tests are
interesting - in many cases polyfills are not perfect replicas of the
native feature, often due to technical feasibility, sometimes due to lack
of resources on the part of the author to cover the entire spec.

Building a polyfill is harder than building the feature natively, since
your code needs to work in all browsers (and by definition not just the
latest ones) whereas the native impl only has to work in one version of one
browser.  At the same time polyfill authors are normally individuals with
limited resources whereas native implementations are created by large teams
within well funded corporations.  Also, the nature of polyfills means it's
possible to retrospectively fix bugs in them much more easily - especially
if they are served from a centrally managed CDN.

In polyfill.io we've looked at the feasibility of testing polyfills with
web platform tests, but in practice almost all polyfills fail those tests,
and yet people still use them successfully.  Obviously it's great when a
polyfill author makes a polyfill that passes WPTs, but since most don't,
making that a condition of acceptance into a community polyfill library
would be problematic.  I guess polyfills might help the testing effort in
other ways?

A