It does not work as a dependency of a package

[mitar]

A package with the following:

Package.onUse(function(api) {
  api.versionsFrom('1.2.1');

  api.use([
    'semantic:ui',
    'flemay:less-autoprefixer',
    'jquery'
  ], ['client']);

  api.addFiles([
    'semantic/custom.semantic.json'
  ], ['client'])
});

Does not generate files inside the package. In fact, it generates a file semantic/custom.semantic.json in the root of the app (but package is inside packages).

[myktra]

There are some recommendations out there to move Semantic-UI into its own local package to keep build times down.

Move as much of your code as possible into many small Meteor packages. Packages rebuild somewhat separately from the main application and other packages, so you can get much faster reloads by breaking up your code. If you are using a large library (e.g. Semantic UI), make sure it is in its own package!

But not sure if this would work given the issue noted above by @mitar (and is it still a problem on 1.4.x?)