add support for extension less JavaScript / CSS files (JS files "in disguise")

[thescientist13]

Type of Change

• New Feature Request
• Documentation / Website
• Improvement / Suggestion
• Bug
• Other (please clarify below)

Summary

As part of testing out integration with Material Web Components in ProjectEvergreen/greenwood-getting-started#42, it was observed that some tools are not including an extension which causes a couple issues

• CSS files that are supposed to be treated as JS files will not return correctly
• JS files that are actually there will not return correctly

Basically, MWC will reference a CSS file as such in JavaScript

.
.
import { styles } from './styles.css';

But the actual file exists as styles.css.js.

Details

As this is non standard behavior, the CSS support should be put into plugin-import-css and for JavaScript, I think it is fine (for now) to include in plugin-node-modules since bare specifiers are the norm there.

[thescientist13]

Or at least document something since this kind of error for a missing .js extension is definitely not helpful / insightful