Grouping Libraries

Libraries should be grouped by scope. A library's scope is either application to which it belongs or (for larger applications) a section within that application.

Move Generator

Don't be too anxious about choosing the exact right folder structure from the beginning. Libraries can be moved or renamed using the @nrwl/workspace:move generator.

For instance, if a library under the booking folder is now being shared by multiple apps, you can move it to the shared folder like this:

nx g move --project booking-some-library shared/some-library

Remove Generator

Similarly, if you no longer need a library, you can remove it with the @nrwl/workspace:remove generator.

nx g remove booking-some-library

Example Workspace

Let's use Nrwl Airlines as an example organization. This organization has two apps, booking and check-in. In the Nx workspace, libraries related to booking are grouped under a libs/booking folder, libraries related to check-in are grouped under a libs/check-in folder and libraries used in both applications are placed in libs/shared. You can also have nested grouping folders, (i.e. libs/shared/seatmap).

The purpose of these folders is to help with organizing by scope. We recommend grouping libraries together which are (usually) updated together. It helps minimize the amount of time a developer spends navigating the folder tree to find the right file.

apps/
  booking/
  check-in/
libs/
  booking/                 <---- grouping folder
    feature-shell/         <---- library

  check-in/
    feature-shell/

  shared/                  <---- grouping folder
    data-access/           <---- library

    seatmap/               <---- grouping folder
      data-access/         <---- library
      feature-seatmap/     <---- library

Sharing Libraries

One of the main advantages of using a monorepo is that there is more visibility into code that can be reused across many different applications. Shared libraries are a great way to save developers time and effort by reusing a solution to a common problem.

Let’s consider our reference monorepo. The shared-data-access library contains the code needed to communicate with the back-end (for example, the URL prefix). We know that this would be the same for all libs; therefore, we should place this in the shared lib and properly document it so that all projects can use it instead of writing their own versions.

  libs/
    booking/
      data-access/           <---- app-specific library

    shared/
      data-access/           <---- shared library

      seatmap/
        data-access/         <---- shared library
        feature-seatmap/     <---- shared library