Pass a React Native view from JS to Obj-C

gistfile1.m

RCT_EXPORT_METHOD(doSomething:(NSNumber *)reactTag)
{
    [_bridge.uiManager addUIBlock:^(RCTUIManager *uiManager, RCTSparseArray *viewRegistry) {
        UIView *view = viewRegistry[reactTag];
        if ([view isKindOfClass:[UIView class]]) {
            [view doSomething];
        }
    }];
}