React 子組件state內數組修改頁面不刷新問題

1.在子組件內對數組進行刪減后打印數據有變化但是頁面沒重新渲染

原始寫法

 deleteBtnClick(index){
        let tempList = this.state.attachList;
        tempList.splice(index,1)
        this.setState({
            attachList: tempList
        });
    }

解決辦法

 deleteBtnClick(index){
        let tempList = this.state.attachList;
        tempList.splice(index,1)
        this.setState((prevState) =>{
            delete prevState.attachList;
            return prevState;
        })
        this.setState({
            attachList:tempList
        })

    }