Errors

All ResourceKit errors extend ResourceKitError and carry a stable code. Codes survive the network - an error raised on the server arrives at the client with its meaning intact.

import { ResourceKitError } from "resourcekit";

try {
  await assign.run(id, { userId });
} catch (error) {
  if (error instanceof ResourceKitError && error.code === "conflict") {
    // someone else edited this record
  }
}

Codes

Code	Means	Typical reaction
`conflict`	The write lost to a concurrent edit; it was rolled back and the winner fetched	Tell the user - see Conflicts
`access_denied`	Outside the caller's access scope, or the resource has no rule	Usually a bug in UI state - the user shouldn't have been able to try
`invalid_input`	A record, patch, or input failed schema validation	Fix the form / the caller
`not_found`	A write addressed a record that doesn't exist	Refresh the view
`result_limit`	A read matched more rows than the server's `maxRows`	Narrow the filter or window with `.take(n)`
`rejected`	The server refused for a business reason (e.g. a server-only action threw)	Show the message
`unsupported`	The resource doesn't support this operation (e.g. `where` on a Stripe-backed resource)	A bug - the typed API normally prevents it; only a stale or hand-built plan reaches here
`transport`	The network failed - retryable; writes queue instead of failing	Usually nothing: offline handling has it
`unknown_resource` / `no_backbone`	Configuration mismatch between client and server	Fix the setup - these shouldn't reach production
`internal`	Anything unexpected server-side	Log it

Error classes

Common cases also have classes for instanceof checks:

import {
  ConflictError,
  AccessDeniedError,
  InvalidInputError,
  NotFoundError,
  MutationRejectedError,
  TransportError,
  UnsupportedOperationError,
} from "resourcekit";

Checking error.code is equally valid and survives serialization boundaries - prefer it in generic handlers.

Where errors surface

Reads: useSynced exposes refresh failures as error (network loss isn't an error - it's status: "offline").
Writes: the run() / mutate() promise rejects, and useAction mirrors it as error / isConflict. The optimistic change is already rolled back by then.
Server-only code: throw ResourceKitErrors (or anything) from action and query implementations - the message travels to the client, the code defaults to rejected/internal.

Errors

Codes

Error classes

Where errors surface

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