Update the duplicate dependency plugin to use the lock file rather than the file system

[laurathackray21]

When analysing duplicate dependencies, the cli will now look at the lock file rather than at the file system.

I've created a new plugin to do this and left the old code as it was so that whoever reviews this can do a side by side comparison. I'll clean up the old code once we're happy with the changes.

The part of the old dependency plugin that generates the statistics (install size, dependency count etc) should remain a separate plugin as this isn't dealing with duplicate dependencies. Also, I think that code is going to have to use the file system to deduce how many esm/cjs modules there are (I don't think it's possible to find this info out from the lock file)

Example screenshot of output before the changes

Example screenshot of output after the changes

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/e18e/cli/@e18e/cli@146

commit: 5d9f666

[43081j]

looks good to me 👍

eventually i think we'd extract some of the resolveDuplicateDependencies/computeParents stuff in a "core" file the action can use too.

future ideas though :D

[dreyfus92]

this looks good, but i'm here wondering if we're gonna add testing after we finish the whole refactor?

[laurathackray21]

Thanks both :) Yeah, we need to make sure this stuff is all covered by tests - I'm gonna do a follow up PR to remove the old duplicate dependency code - I'll have a look at the tests when I do that