React troubleshooting

The form is unstyled

Import form0-react/index.css once in the application entry point. Confirm that the bundler allows CSS imports from dependencies.

A field says it is unsupported

Confirm that the type is listed in the Core field catalog. If the type is known but intentionally replaced, verify that the component is registered in the same FieldRegistryProvider subtree as FormRenderer.

The schema fails during rendering

FormRenderer validates schema.form and requires form.elements. Use form0 validate before loading the schema in the application.

Worker mode cannot load the worker

First return to engineMode="main-thread". For Vite, keep the worker constructor statically analyzable and exclude form0-react from dependency optimization as shown in the maintained web starter. Other bundlers must support ESM module workers based on new URL(..., import.meta.url).

Custom workerUrl and createWorker options are not part of the public FormRenderer API.

Updates do not appear during local package development

Rebuild form0-react, restart the consuming development server, and clear only that bundler’s dependency cache if necessary. Vite can retain an optimized copy of a linked or previously installed package.

Submission does not run

Check that onSubmit is a function, the form is in edit mode, submitBlockedReason is empty, and the validation summary has no errors. For overlays returning a promise, handle rejection so the application can present the failure while the overlay remains open.