feat: add "install" command

[fregante]

Description

What's your workflow when adding a dependency to a package?

If it's a new one, I just run npm install foo -w libs/my-package

If any of the other packages already use "foo", I have to hunt down the dependency and copy-paste the version into libs/my-package/package.json. Only then run npm install

This is tedious and error prone.

Suggested Solution

Add syncpack install foo -w libs/package

This can automatically follow its rules for version matching, update the relevant package.json, and then call npm install to actually install the dependency.

Optional comments

I cannot rely on syncpack to fix the issue after the first "latest version" install because npm often fails to properly update the lockfile.

Code of Conduct

• I agree to follow the Code of Conduct

[JamieMason]

I cannot rely on syncpack to fix the issue after the first "latest version" install because npm often fails to properly update the lockfile.

Can you expand on this part? I didn't quite understand what it is, thanks.

[fregante]

My project has currently "no issues" thanks to syncpack. But today I went to update eslint. By mistake I ran npm install eslint -D in one of the libs, immediately breaking havoc. I don't know why npm still isn't able to correctly resolve the tree but here's what happened:

• it installed eslint inside libs/*/node_modules/eslint rather than node_modules/eslint
• it duplicated eslint many times, with npm ls eslint showing up once per lib, without "deduped" next to it
• an eslint plugin ended up being unable to locate eslint itself

This is the kind of issues that are generally solved by deleting node_modules, the lockfile, and starting over. Unfortunately due to some older dependencies we're stuck on, I don't have the luxury of being able to do so anytime I want.

[fregante]

Oh, and the best thing is that even after I run syncpack fix, npm is still unable to install the correct dependencies, with npm install exiting without errors but then npm ls eslint showing ELSPROBLEM next to each eslint.

The solution is to reset the lockfile to what I have on main and then run npm install again. Maybe clearing node_modules first.

[fregante]

To recap, syncpack could work around this issue by offering a way to add dependencies that does not involve manually editing package.json nor running npm install DEP on the repo.

For example:

syncpack install eslint -w libs/mylib

Could add the correct version (the version I use in other libs) to libs/mylib and then run npm install.