You could do a separate project for each and change to the relevant Root Directory as needed when setting them up. I hope that helps!

The appropriate filter will be automatically inferred based on the configured root directory.

For future reference, the root directory needs to be the directory of the sub-package within the monorepo, and the build/install directories need to be specified relative to that.

It is obvious now, of course ...

• Project type: other
• Root directory: the root of the individual package being deployed - package/x
• Build build ../../
• Install ../../

Thanks for coming back with the solution, and helping everyone else in the community @leegee!

It's been a long 24-hours, and eventually I discovered that the problem was I had been advised elsewhere to use an .npmrc file with the contents worksapces=true.

That was a bad idea, and broke everything.

By the time I had discovered that, I had already switch to using Turbo, which was a straight forward process, just adding a turbo.json file with a minimal configuration.

Having done that, I turned off all the 'zero configuration' options in dashboard, set 'Framework' to 'other,' and let the root directory blank. That allowed me to use a vercel.json without warnings and confusion:

1
  "installCommand": "npm install",
2
  "buildCommand": "npx turbo run build",
3
  "outputDirectory": "packages/client/build",

This works.

Note to self: the log output running vercel build is actually running the package.json script vercel-build...!

Creating a Vercel Postgres instance has proven to be straight forward: now some fun with hooking up serverless functions! See you in my next confused post...!

Thanks Lee