Validate individual components against JsonSchema and produce warnings in DevTools

[olemartinorg]

Extracted from #648. We should bring a copy of the component JsonSchema into app-frontend, and validate all components in a layout file against that, spitting out errors in DevTools if any.

[bjosttveit]

How should app-frontend load the schemas? I can see a few options:

1. Bundle the schemas with altinn-app-frontend.js
   • This file is already quite large, and this would bring an additional ~230kb
   • It is unnecessary to load in prod, but if done this way it would not be optional
   • It would always be up to date with the actual frontend version used, but risks differing from the schema used in the layout file giving feedback in the editor.
2. Load the schema using the same url as the layout-files have.
   • It could either be hard-coded in app-frontend or picked out from the layout-file from the app.
   • This method risks using the incorrect version depending on what frontend-version the app is using. (frontend version can be set to a specific version and will not necessarily be on the latest version)
   • If not bundled, it can be loaded only in dev/tt02 or only when dev-tools is opened (or both). Additional loading time would be less of an issue.
3. We could move the schemas to the dist folder so the schemas would be tied to the frontend-version and would be deployed to cdn alongside altinn-app-frontend.js.
   • This is especially relevant since schemas are auto generated and can be assumed to be up to date with every version.
   • This would have the same benefit as 2. with the added benefit of always corresponding to the actual frontend version used.
   • It would be a breaking change for the schema url used in the layout file, since to be guaranteed to have the same schema used to check in the editor as in dev-tools you would need to update the url in each layout file. We would likely need to change the url for v4 anyways if we want to keep support for v3 for a while, and this change should be handled automatically using an upgrade tool either in studio or cli or both.
   • Downside is more storage use in cdn, but since it looks like we are finally ditching GitHub pages this may not be an issue very soon?

Any thoughts @olemartinorg @tjololo ?

[olemartinorg]

Agree whole-heartedly on alternative number 3. We would also need tooling (such as the upgrade tool) to update $schema references in layout files in apps when changing the frontend version.

[olemartinorg]

Tested OK! 🥳 There's a bit of mixing between norwegian and english right now in the log, but IMO that's fine.