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
For Angular projects, you should use the @nrwl/angular:move generator instead.
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