Config with a stackblitz field in package.json

[patak-dev]

The original idea is from @antfu. In Vitest we are using StackBlitz to add online playgrounds for the examples. See https://vitest.dev/guide/#examples.

In each example in https://github.com/vitest-dev/vitest/tree/main/examples, we need to add a .stackblitzrc file. This increases the cognitive load for new users because they need to understand this extra file. In some examples, a project may have only a handful of files so adding another one is not free.

An idea to avoid this issue would be to allow to configure the playground with a stackblitz field in package.json. This is standard for other tools like prettier, eslint, etc.

[SamVerschueren]

It would be awesome to have support for stackblitz property in package.json. However for now, I think you can get away with query params alone while still preserving the same functionality.

It seems that the .stackblitzrc in the examples is identical and always this

{
  "installDependencies": true,
  "startCommand": "npm run test:ui"
}

installDependencies is true by default if there's a package.json, so that's already covered. The startCommand can be replaced with ?terminal=test:ui in the query params.

This will not work if you use the "open from github" functionality where you just replace github.com with github.stackblitz.com in the examples directory. So for that to work, we need the package.json#stackblitz support.