breeze-client / isConcurrencyError

Function: isConcurrencyError()

isConcurrencyError(error): boolean

Defined in: src/manager/entity-manager.ts:154

Whether an error is an optimistic concurrency conflict - a row changed or deleted by someone else after this client read it.

try {
  await em.saveChanges();
} catch (e) {
  if (isConcurrencyError(e)) {
    // re-read and let the user decide; retrying the same save would fail the same way
  }
}

This is exact rather than approximate: it is true only when the server said so with ProblemTypes.concurrencyConflict, never inferred from the status code or the message. A 409 from a duplicate key is not a concurrency conflict, and matching on message text breaks when the ORM, database or server version changes.

A Breeze .NET server sends this for EF Core's DbUpdateConcurrencyException and NHibernate's StaleObjectStateException. A server that does not send a type - any pre-3.0 Breeze server, and most non-Breeze ones - returns false here, and there is nothing reliable to use instead.

When the conflict names the rows involved, they are on entityErrors with the entities attached:

const stale = (e.entityErrors ?? [])
  .filter(ee => ee.errorName === "ConcurrencyError")
  .map(ee => ee.entity);

Parameters

error

any

The rejection value from a Breeze call - typically a SaveError.

Returns

boolean

true if the server identified this as a concurrency conflict.