Adding an "only" option

[arantes555]

Hello,
However, for my project, I needed the ability to limit the resolution of node_modules to only modules matching a pattern, so I added this option. The implementation is very straightforward, using String.prototype.match.

Using it is very simple. It works with both strings and regexes:

{
  entry: 'samples/only/main.js',
  plugins: [
    nodeResolve({
      only: [ 'test' ]
    })
  ]
}

import test from 'test' // will be bundled
import test2 from 'test2' // /!\ will be bundled
import mytest from 'mytest' // will NOT be bundled

{
  entry: 'samples/only/main.js',
  plugins: [
    nodeResolve({
      only: [ /@scoped\/.*/ ]
    })
  ]
}

import test from 'test' // will NOT bundled
import mytest from '@scoped/mytest' // will be bundled
import mytest2 from '@otherscope/mytest' // will NOT be bundled

[keithamus]

Hey @arantes555 - this looks like a good PR. My question is, does jail not help you here?

Also this PR has some conflicts - so if you think we should really add this it would be great to get it rebased 😃

[arantes555]

Hi @keithamus ! Thanks for checking this out 😄

Nope, the jail option does not cut it for me. For example, if I want to rollup a node module called foo and only it, if I set the jail option to ./node_modules/foo, it is also going to rollup what is under ./node_modules/foo/node_modules, which I do not want (and what's actually in there depends on how npm decides to dedupe packages...). Maybe I missed something and jail is actually enough for this usecase?

Indeed, there are some merge conflicts, which is to be expected as the PR is more than a year old 😜 .
I'll get around to rebasing it sometime next week! Thanks :)

[arantes555]

@keithamus : branch has been rebased, and some cleanup has been done :) I believe it's good to merge on my end!

[keithamus]

Im happy with this - but I'll ask @lukastaegert for a second 👍 before we go ahead and merge.

[lukastaegert]

There seems to be some overlap with rollup's own "externals" function but I still see some use-cases for this feature. One minor performance suggestion, otherwise 👍

[lukastaegert]

For performance reasons it might also make sense to initially convert all entries to RegExp (in L.47 where it will only happen once) and then use pattern.test(id) instead (which will make all invocations faster, cf. e.g. https://stackoverflow.com/a/10940138)

[arantes555]

@lukastaegert : I just pushed a minor edit with your suggestion !

[lukastaegert]

Nice!

[keithamus]

3.3.0 😄