[icon-themes] Support for folder / directory names in file associations (Icon themes)

[ghost]

#12493 specifies globs in file associations, but I'd really like to match based on folder name as well.

For example, Ember uses config/environment.js which in a perfect world the File Icon API would consume into:

<div class="monaco-icon-label file-icon environment.js-name-file-icon js-ext-file-icon ext-file-icon config-dir-file-icon javascript-lang-file-icon file-icon">
<!-- ::before -->
</div>

File icon packs would then just do this: { "config/environment.js": "../icons/ember.svg" }.

[aeschli]

Good suggestion. Happy to take a PR.

[ghost]

I can start work on this STAT, which files need updating?

https://github.com/microsoft/vscode/blob/1.62.2/src/vs/editor/common/services/getIconClasses.ts

[aeschli]

Yes that one hopeful is used by everyone.
The css rules are created in https://github.com/microsoft/vscode/blob/main/src/vs/workbench/services/themes/browser/fileIconThemeData.ts

[ghost]

We do need to agree for a syntax on this - is <directory>/ prefix okay for all cases - folderNames folderNamesExpanded fileExtensions fileNames?

[aeschli]

I'm fine with allowing it for all.
One thing to pay attention to is what happens if there are multiple associations that match a resource name/ path.
The current rule is:
A file name match is preferred over a file extension match which is preferred over a language match.
This is implemented by the number of css classes that are matched.

The question is how folder matches are treated:

• folder/name is stronger than just name
• folder/extension is stronger that extension, but does it beat name?

[ghost]

I also do want to propose a "./" prefix for root files like Heroku's ./app.json. Is there a way to implement that?