[proposal] Use W3C CSS Index as source

[ideadapt]

Hi there,
I very like the idea of your project. For some time I was looking around to solve that problem somehow. Then I stumbled upon https://drafts.csswg.org/indexes/#properties and your repo on the same day!
Inspired by your work I created a basic implementation, that scrapes the w3c URL. I think if we can avoid depending on w3schools (or any other interlink between us and w3c) thats a good thing :) This way we are more up to date and closer to the truth.

What did I do?

• Introduced typescript
• es6 target platform
• Use w3c index for scraping
• Tell the scraper what css version/modules you are interested in to only work on them
• Output json features a version per property (hence you can also filter at that stage)

Whats still todo?

• Cleanup source
• Tests
• Define how to resolve value tokens (e.g. percentage or length) which are not literal values

Hope you like it :D

[ideadapt]

@a-axton It seems like my solution to the problem is somehow obsolete. I discovered https://github.com/w3c/csswg-drafts/blob/master/css21/properties/properties.db, which is a far more practical format to parse ... It seems like they already have some kind of a parser, but I haven't found one publicly available.
And also they only have CSS 2.1 properties listed, there, didn't find same thing for CSS3 neither.