Function assertIsMounted

docs/external/js/react-dom.development.js:3068–3074

(fiber)

  }

  function assertIsMounted(fiber) {
    if (!(getNearestMountedFiber(fiber) === fiber)) {
      {
        throw Error( "Unable to find node on an unmounted component." );
      }
    }
  }

  function findCurrentFiberUsingSlowPath(fiber) {
    var alternate = fiber.alternate;