Document src/node_modules as official solution for absolute imports

After a long discussion in #741 it seems to me that src/node_modules seems like the best solution for absolute imports.

It has the following benefits:

• Doesn’t rely on symlinks (they don’t work well on Windows).
• Works with IDEs and any existing tooling because it relies on Node resolution mechanism.
• If you really want to, you can run ln -s src/node_modules src/packages and use the “nicer” packages (or any other) folder.

This issue is a call to help to make this approach the official one. We need to:

• Document it
• Make Jest preprocess this subfolder #607
• Make Jest run tests in it #1042
• Fix any other integration issues we find

If you want to work on either please leave a comment and then submit a PR! Cheers.

[alex35mil]

In my mental model node_modules is something I can easily rm -rf and regenerate w/o worries to lose anything. I never expect any app code in there. A lot of various configs ignore it for the same reason: in most of the cases, it’s something not related to user’s code. Also, usually you have to move a whole app in this directory.

[icopp]

For absolute imports, it seems like it’d be a lot better to have some kind of special prefix and set up webpack’s alias functionality for it. For example, my personal projects use:

{
  resolve: {
    alias: {
      "@": path.resolve(__dirname, 'src')
    }
  }
}

…after which you can reference files via…

import App from '@/App' // the file is at `src/App/index.jsx`

You can also inject the same schema into Jest:

"moduleNameMapper": {
  "^@/(.*)$": "<rootDir>/src/$1"
}

It keeps a clear distinction from npm-tracked node_modules, avoiding the “I can’t get it to work and I don’t understand why” potential of having overlapping names or having imports start with just ./.