内部的范围错误会以Subpub模式做出反应，我会在Subscribe函数中更新某些项目并获得错误的状态

Question

我将React 16.5与subpub lib一起使用。

componentDidMount() {
    that = this;
    mystate = this.state.OrderItems;
    PubSub.subscribe(this.props.topic, this.addData);
}

addData(msg, data) {

    for (let i of data) {
        console.log(i);
        console.log(mystate);
        let exist_item = mystate.filter(item => item["product_id"] == i["id"]);
        console.log(exist_item);
        if (exist_item.length >= 1) {
            exist_item[0]["amount"] += 1;
        } else { 
            let tmp = {
                "id": v4(),
                "name": i["name"],
                "amount": 1,
                "item_price": i["price"],
                "product_id": i["id"]
            };
            console.log(tmp);
            mystate.push(tmp);
            console.log(mystate);

        }
    }
    that.setState({
        OrderItems: mystate
    });                   ////1.here I change update the state and rerend
}

componentDidUpdate() { 
    that = this;                  ///2.odd thing happens here
    mystate = this.state.OrderItems;
    console.log(this.state.OrderItems);///here I get []
    console.log(mystate);             ///here I get []
}

我得到的componentDidUpdate（）函数：

Card.js:65 []
Card.js:66 []

我已经更新了数组mystate，但是当我检查componnentDidUpdate（）时，那里有空字符串。

ps：我之所以不会像PubSub.subscribe(this.props.topic, this.addData.bind(this));那样进行绑定，是因为绑定时发生了巨大的内部错误