onImport argument includes top-level (importing) file

[jmm]

Hello,

With postcss@5.2.5 and postcss-import@8.1.2 I'm getting the top level file that's passed to postcss in the argument to onImport, which is not what I expect. It's documented as:

array of imported files

Which I interpet as: the files referenced by @import rules.

So say I have 2 files like this:

top-level.css

@import "./imported.css";

imported.css

/* */

In onImport I get an array containing the paths for both files.

Is that intentional? If so, can you please document it. And if that's the case, can you commit to it always being the first element in the array?

Thanks!

[RyanZim]

@MoOx Related: postcss-cli needs to know which file is the parent of the import.

postcss-cli formerly relied on the (undocumented) fact that inside onImport, this.from was the parent. This is no longer so. postcss/postcss-cli#44

Either the parent must be guaranteed to be the first element, or onImport should receive a second argument parent. If we go with the first option, the current implementation would have to be changed since Object.keys() technically isn't guaranteed to be deterministic.

[RyanZim]

X-ref: #233

[RyanZim]

@jmm We added a dependency message for each import in #241. This was released as https://github.com/postcss/postcss-import/releases/tag/8.2.0.

You can access the messages by filtering result.messages:

var postcss = require('postcss');
postcss([ require('postcss-import') ])
    .process(css, { from: 'src/app.css', to: 'app.css' })
    .then(function (result) {

        // Get list of imports:
        var imports = result.messages.filter(message => message.type === 'dependency')

        // Write File...
    });

imports would be an array of objects, each with this form:

{
  type: 'dependency',
  file: 'ImportedFile.css',
  parent: 'FileContainingTheImport.css',
}

In the future, I might deprecate or remove onImport. For now, I think I'll just leave things as they are and recommend using the dependency message instead.