Dependencies for non-ES modules

[Ian Hickson]

Suppose an ES6 module loads a CSS file as an import, and that CSS file has 
an @import rule of its own.

The CSS @import rule semantics are such that the file must be interpreted 
as CSS. It's not an open-ended import like ES6. Also, the load must not be 
deduped; each style sheet that is @imported will create a new independent 
CSSStyleSheet object.

I'm not sure how to implement this using the ES6 Loader (should the ES6 
loader even be used for this? It seems like it should, in case we later 
support CSS referencing ES6 modules, e.g. for Web Components).

How do I mark a dependency with metadata? If I return an object in the 
"deps" field of the "instantiate" hook's result object, and then pass that 
through the "normalize" hook, the GetOrCreateLoad() function applies 
ToString() to it, so I can't pass any metadata through to "fetch", where 
I need it. (If I translate the metadata in the object passed in "deps" in 
the "normalize" hook, that string gets exposed as the module name, which 
is rather suboptimal.)

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'