Function encodeErrorForBoundary

packages/react-server/src/ReactFizzServer.js:1169–1200

(
  boundary: SuspenseBoundary,
  digest: ?string,
  error: mixed,
  thrownInfo: ThrownInfo,
  wasAborted: boolean,
)

}

function encodeErrorForBoundary(
  boundary: SuspenseBoundary,
  digest: ?string,
  error: mixed,
  thrownInfo: ThrownInfo,
  wasAborted: boolean,
) {
  boundary.errorDigest = digest;
  if (__DEV__) {
    let message, stack;
    // In dev we additionally encode the error message and component stack on the boundary
    if (error instanceof Error) {
      // eslint-disable-next-line react-internal/safe-string-coercion
      message = String(error.message);
      // eslint-disable-next-line react-internal/safe-string-coercion
      stack = String(error.stack);
    } else if (typeof error === 'object' && error !== null) {
      message = describeObjectForErrorMessage(error);
      stack = null;
    } else {
      // eslint-disable-next-line react-internal/safe-string-coercion
      message = String(error);
      stack = null;
    }
    const prefix = wasAborted
      ? 'Switched to client rendering because the server rendering aborted due to:\n\n'
      : 'Switched to client rendering because the server rendering errored:\n\n';
    boundary.errorMessage = prefix + message;
    boundary.errorStack = stack !== null ? prefix + stack : null;
    boundary.errorComponentStack = thrownInfo.componentStack;
  }
}

function logPostpone(
  request: Request,