var partialState = getDerivedStateFromProps(nextProps, prevState); { // 對一些錯誤格式進行警告 warnOnUndefinedDerivedState(ctor, partialState); } // Merge the partial state and the previous state. // 判斷getDerivedStateFromProps返回的格式是否為空,如果不為空則將由原的state和它的返回值合并 var...