RFC: `modular check`

[Sunil Pai]

modular check <dir?> a command to check the state of a modular project, and spot warnings/errors. This isn't a lint/typecheck for code, but you could consider it a similar tool for project structure and configuration. It should spit out warnings and errors; it should have a recommended fix for each violation, and it should ideally provide an option to automatically fix it. It isn't meant to be extensible, but we can revisit that decision later.

This issue is about listing every single violation it could detect (which is also a good exercise in enumerating the feature boundaries of modular)

• error: The root folder must contain a package.json with a value:

"modular": {
  "type": "root"
}

• warning: the root package.json should have installed modular-scripts, eslint-config-modular-app, eslint, typescript, prettier, react/react-dom (and its types)
• error: all workspaces must start with packages
• warning: every path that matches the glob path of "workspaces" must have a package.json. This file, if possessing a "modular" field, must have the value { "type": "view" }or { "type": "app" }
• error: there must be a tsconfig.json file at the root
• warning: the root tsconfig should extend "modular-scripts"
• warning: the root tsconfig should include the src of every workspace at least.
• error: no tsconfig, including the root one, should mark isolateModules: true
• warning: the root eslint config should extend "modular-app"
• warning: .prettierignore must ignore /dist, (and all apps' public?)
• warning: eslintignore must ignore /dist
• warning: if @finos/perspective is installed, you should also install @finos/perspective-webpack-plugin
• @manypkg/cli check is a good idea, maybe we should just run that (with opt-out?)

Will keep updating this list as and when, open to ideas.