Add importable scripts

[cvanem]

Allow scripts to be imported from a file as an alternative to the standard object hash in the packages.json scripts field. Also define the basic structure of the imported file.

RFC
Documentation: yarnpkg/website#951
PR: yarnpkg/yarn#7284

[arcanis]

Hey! Thanks for the suggestion 😃 I do have one big concern, however: this proposal makes it impossible to statically know what scripts are available. We would always have to execute the Javascript code to figure it out.

[cvanem]

@arcanis Yes, I suppose that is another drawback that should be added. Is this concern due to a performance hit or something else? The Javascript code would only be executed if a filename input is provided.

[cvanem]

@arcanis Hey just following up on this. Can you tell me how likely it is that this PR will be accepted anytime soon? The reason I am asking, is that we are currently evaluating some options for cleaning up our scripts. See mui/material-ui#15497

If this is not going to be accepted, then I would like to resolve any issues so it can be accepted, or look at other options, such as using nps.

[zkochan]

This is one of the reasons I added support of package.yaml to pnpm (although I am still not sure that was a good idea). But a yaml file (or a json5 file), also satisfies your requirements.

You can write scripts like this:

scripts:
  # This is some comment
  test: >-
    pnpm recursive test
    --reporter append-only
    --workspace-concurrency 1
    --filter ./packages
    --filter ./privatePackages
build: pnpm recursive run tsc