Alternative fix for #3952

[Rich-Harris]

This is an alternative to #3965 — was easier to do as a separate PR than to make commit suggestions. Rather than each handler needing to await response.json(), we can just change the return value from the api helper to make it a valid shadow endpoint response.

I found one other issue with the current version of the app. If you patch or delete a todo with JS disabled, the URL will update to /todos?_method=PATCH. This is no good — reloading the page will cause an error, because method overrides can't be used with GET requests. To fix that, I changed the handlers so that they're redirecting back to /todos instead (which we can do, because we're not using the return values for anything — we're relying on invalidation instead).

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[Rich-Harris]

Gah, I guess this doesn't have any error handling, since we're not just returning the response directly

[geoffrich]

Thanks, this seems cleaner!

Gah, I guess this doesn't have any error handling, since we're not just returning the response directly

I don't think that's a dealbreaker, since even if we return a non-successful response from the endpoint, we don't do anything with it on the page. We're not providing an error handler to the enhance action, and the page isn't exposing any error props to be populated by the endpoint response. It would be good to have more robust error handling in the demo app, but maybe we could look at that in a separate PR?

[Rich-Harris]

Yeah, you're right, we need to improve error handling all round. Fine line between doing things 'right' and making the example too verbose to be easily understood by a newcomer