[css-shadow-parts-1] part should be a superglobal in the HTML spec

[fergald]

spec

Update the DOM spec.

[NullVoxPopuli]

I arrived at this draft from a few links about @apply being abandoned. After reading this spec, I, in no way, see how this is related -- it doesn't solve the same problem.

The path I took to get here:

• https://github.com/pascalduez/postcss-apply
• click Alternative Solutions (Originial CSS Shadow Parts)
• click the link at the bottom that replaces the above document here
• scroll down to the github link, which links to this GH issue

I'm confused. I want to compose CSS classes :-\

[fergald]

@NullVoxPopuli Sorry, I don't know why this is listed as an alternative solution (I am not at all familiar with postcss-apply). Please take that up with the authors of the postcss-apply doc.

[tabatkins]

The reason is that my blog post about abandoning @apply says precisely that. ^_^

The motivating use-case for @apply was passing bags of properties into custom elements, so you didn't have to reinvent all of CSS as custom properties just to allow arbitrary styling of something inside a shadow tree. That use-case was replaced by ::part().

The more general use-case of using @apply to compose classes, however, isn't addressed by this. (And @apply is still bad for that, for all the reasons I gave in my blog post. We probably want to eventually do @extend to address that case.)

[annevk]

@fergald any ETA on this? This feature has shipped reportedly so this seems overdue. If it's superglobal it should be in DOM probably.

[fergald]

@mfreed7 @domenic Please take a look.

[mfreed7]

@mfreed7 @domenic Please take a look.

LGTM to make part superglobal.