npm update unlinks linked packages

Question

I have a project, which consists of one root node package containing subpackages linked together by npm link - these subpackages depend on each other (listed in package.json dependencies) and the structure basically looks like this:

-rootpackage
--subpackageA
--subpackageB

Lets say subpackageA has dependency on subpackageB, so I link them to avoid publishing/reinstalling subpackageB in subpackageA after every change in the source of subpackageB. The link works just fine until I run npm update in subpackageA, which causes the subpackageB to be unlinked.

Now, I see two options:

1. I can theoretically run the npm link operation after each npm install or npm update to ensure the links are always present. This works with postinstall in case of installation, but in case of an update the postinstall is not called. I don't know any postupdate command for npm, which is to be called after update.
2. Maybe there is a way to do this more cleverly, perhaps with yarn, which I am also using, in a way, that it kind of prevents unlinking or excludes the update for my subpackages, so I don't lose the links between my subpackages, but right now I am not aware of such a way.

Is there any way to make one of those options work or any other way to solve this problem ? I need to keep this and other links so we don't have to run npm link after every installation/update. I can't really find information about this issue anywhere. Btw I am using Node 6.4.0 and NPM 3.10.3.

Answer 1

So the solution is to use Yarn Workspaces or maybe project like Lerna.

Yarn Workspaces is a utility that expects a structure similar to what was described in the question and which maintains the linking subpackages and root automatically. It is very easy to set up (just 2 lines in root package.json and executing yarn for the first time) and after it you don't have to worry about upgrade or install at all, the links stay in place unless you delete them manually.

Lerna expands on that and provides you with additional tooling for managing multipackage projects. It can use Yarn Workspaces internally for the linking if you use yarn but it is not a requirement and works fine with npm. Just make sure to have Git because last time I checked Lerna didn't work with SVN or other VCSs.