function getSingularSelector()

in packages/relay-runtime/store/RelayModernSelector.js [68:135]

• 63 lines of code
• 14 McCabe index (conditional complexity)

function getSingularSelector(
  fragment: ReaderFragment,
  item: mixed,
): ?SingularReaderSelector {
  invariant(
    typeof item === 'object' && item !== null && !Array.isArray(item),
    'RelayModernSelector: Expected value for fragment `%s` to be an object, got ' +
      '`%s`.',
    fragment.name,
    JSON.stringify(item),
  );
  const dataID = item[ID_KEY];
  const fragments = item[FRAGMENTS_KEY];
  const mixedOwner = item[FRAGMENT_OWNER_KEY];
  const isWithinUnmatchedTypeRefinement =
    item[IS_WITHIN_UNMATCHED_TYPE_REFINEMENT] === true;
  const mixedClientEdgeTraversalPath = item[CLIENT_EDGE_TRAVERSAL_PATH];
  if (
    typeof dataID === 'string' &&
    typeof fragments === 'object' &&
    fragments !== null &&
    typeof fragments[fragment.name] === 'object' &&
    fragments[fragment.name] !== null &&
    typeof mixedOwner === 'object' &&
    mixedOwner !== null &&
    (mixedClientEdgeTraversalPath == null ||
      Array.isArray(mixedClientEdgeTraversalPath))
  ) {
    const owner: RequestDescriptor = (mixedOwner: $FlowFixMe);
    const clientEdgeTraversalPath: ?ClientEdgeTraversalPath =
      (mixedClientEdgeTraversalPath: $FlowFixMe);

    const argumentVariables = fragments[fragment.name];
    const fragmentVariables = getFragmentVariables(
      fragment,
      owner.variables,
      argumentVariables,
    );

    return createReaderSelector(
      fragment,
      dataID,
      fragmentVariables,
      owner,
      isWithinUnmatchedTypeRefinement,
      clientEdgeTraversalPath,
    );
  }

  if (__DEV__) {
    let stringifiedItem = JSON.stringify(item);
    if (stringifiedItem.length > 499) {
      stringifiedItem = stringifiedItem.substr(0, 498) + '\u2026';
    }

    warning(
      false,
      'RelayModernSelector: Expected object to contain data for fragment `%s`, got ' +
        '`%s`. Make sure that the parent operation/fragment included fragment ' +
        '`...%s` without `@relay(mask: false)`.',
      fragment.name,
      stringifiedItem,
      fragment.name,
    );
  }

  return null;
}