This is not important but it seems that this if statement is superfluous since `typeof` always returns a string. 

https://github.com/facebook/react/blob/553440bd1578ef71982c4a10e2cc8c462f33d9be/packages/react-devtools-shared/src/hydration.js#L246

case 'nan':
    case 'undefined':
      
      
      cleaned.push(path);
      return {
        type,
      };
    default:
      return data;
  }
}
export function fillInPath(
  object: Object,
  data: DehydratedData,
  path: Array<string | number>,
  value: any,
) {
  const target = getInObject(object, path);
  if (target != null) {
    if (!target[meta.unserializable]) {
      delete target[meta.inspectable];
      delete target[meta.inspected];
      delete target[meta.name];
      delete target[meta.preview_long];
      delete target[meta.preview_short];
      delete target[meta.readonly];
      delete target[meta.size];
      delete target[meta.type];
    }