Update API usage of the view helpers by changing javascript_packs_with_chunks_tag and stylesheet_packs_with_chunks_tag to javascript_pack_tag and stylesheet_pack_tag. Ensure that your layouts and views will only have at most one call to javascript_pack_tag or stylesheet_pack_tag. You can now pass multiple bundles to these view helper methods.

There is always a way to work around that by doing expr as unknown as T, but it stops people making basic errors.

Because constants in Ruby aren't meant to be changed, Ruby discourages you from assigning to them in parts of code which might get executed more than once, such as inside methods.

Enforces better architecture

Trust me, I thought a lot about #validate and its semantics, and I am gonna make it even more "SRP" by making Form#errors and #valid? semi-public. All that happens via #validate reducing the possible wrong usage for users.

The only solution that I can see is to ensure that each user gets their own set of stores for each server-rendered page. We can achieve this with the context API, and expose the stores like so: <script> import { stores } from '@sapper/app'; const { page, preloading, session } = stores(); </script> Calling stores() outside component initialisation would be an error.

This would be cumbersome, and would encourage developers to populate stores from inside components, which makes accidental data leakage significantly more likely.

which makes it much harder to accidentally keep logged-in state visible after a client-side logout

There was a major refactoring in the resolver (https://github.com/webpack/enhanced-resolve). This means the resolving option were changed too. Mostly simplification and changes that make it more unlikely to configure it incorrectly.