例えばrenderを条件で非表示・表示わけさせたいときにreturnしてしまうと
render() { if (hoge === bar) { return; }
Table(...): Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.
のエラーとなる。
reactjs - Is it possible to return empty in react render function? - Stack Overflow
return (null);
とすれば行けた!