feat: export proper ErrorResponse type

[brophdawg11]

This handles the callout in remix-run/remix#7238 which has come up a few times in discord as well.

We always wanted class ErrorResponse to be an implementation detail since it serves no runtime purpose in userland. We naively thought isRouteErrorResponse's type narrowing would be sufficient, and is in the simple case:

function ErrorBoundary() {
  let error = useRouteError();
  // 🙁 error is un-typed

  if (isRouteErrorResponse(error)) {
    // yay typed! 😀
  }
}

However, this is limited since you can't build abstractions around these errors:

function ErrorBoundary() {
  let error = useRouteError();

  if (isRouteErrorResponse(error)) {
    return <MySuperCoolErrorResponseUI error={error}
  }
}

// ❌ Uh-oh - we don't have the class available to us to type this function
function MySuperCoolErrorResponseUI(error: any) {
  return <>{/*...*/}</>;
}

The class was always marked @private and wasn't ever intended to be used, so this PR moves the class to an UNSAFE_ErrorResponseImpl export. Because it was always marked "private", I don't consider this a breaking change.

That frees up the ErrorResponse name so we can export a type of an instance of the class, which properly excludes the private properties:

export type ErrorResponse = InstanceType<typeof ErrorResponseImpl>;

Then we can export this ErrorResponse type out through @remix-run/react as well.

Main changes are in utils.ts - the rest is just bubbling the name changes out and exporting the new type out through the dependent packages

[changeset-bot]

🦋 Changeset detected

Latest commit: 356f2a5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
react-router-dom-v5-compat	Patch
react-router-native	Patch
react-router-dom	Patch
react-router	Patch
@remix-run/router	Patch

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[brophdawg11]

These should have been private all along, but since the entire class was a "private" implementation detail I think I glossed over the field specifiers. Marking them private ensures the type below doesn't include them.

[github-actions]

🤖 Hello there,

We just published version 6.16.0-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 6.16.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!