无法访问Facebook Graph Api响应的数据-reactJs

Question

我整天都在尝试找到有关如何访问Facebook嵌套响应的解决方案。我将FB.api与嵌套请求一起使用，并且得到了响应，没关系。

这里是我从Facebook Graph Api获得的回复示例

{
  "insights": {
    "data": [
      {
        "name": "page_fan_adds_unique",
        "period": "month",
        "values": [
          {
            "value": 272,
            "end_time": "2019-10-08T07:00:00+0000"
          },
          {
            "value": 270,
            "end_time": "2019-10-09T07:00:00+0000"
          }
        ],
        "title": null,
        "description": "The number of new people who have liked your Page.",
        "id": "1021596371302281/insights/page_fan_adds_unique/month"
      },
      {
        "name": "page_fan_removes_unique",
        "period": "month",
        "values": [
          {
            "value": 450,
            "end_time": "2019-10-08T07:00:00+0000"
          },
          {
            "value": 453,
            "end_time": "2019-10-09T07:00:00+0000"
          }
        ],
        "title": null,
        "description": "Unlikes of your Page.",
        "id": "1021596371302281/insights/page_fan_removes_unique/month"
      },
      {
        "name": "page_views_total",
        "period": "month",
        "values": [
          {
            "value": 6430,
            "end_time": "2019-10-08T07:00:00+0000"
          },
          {
            "value": 6339,
            "end_time": "2019-10-09T07:00:00+0000"
          }
        ],
        "title": null,
        "description": "The number of times a Page's profile has been viewed by logged in and logged out people.",
        "id": "1021596371302281/insights/page_views_total/month"
      }
    ],

我正在使用react。我在父组件中进行了APi调用，如下所示：

async componentDidMount() {
    const resI = await axios.get(
      'https://graph.facebook.com/MyID/',
      {
        params: {
          access_token: process.env.REACT_APP_FACEBOOK_ACCESS_TOKEN,
          fields:
            'insights.metric(page_fans, post_engaged_users, post_impressions_unique, page_fan_adds_unique, page_fan_removes_unique, page_views_total, page_fans_gender_age, page_fans_country, page_fans_city, page_fans_locale).period(month)'
        }
      }
    );
    this.setState({insights: resI.data});
    console.log(this.state.insights.insights.data[0].values[1].value); //I Get 270. It working in the parent component
  }

我将从API获得的数据作为对其他组件的支持

....
<div>
   <GlobalPerf insights={this.state.insights} />
</div>
......

这里是问题开始的地方。我无法访问子组件中的values数组中的值]

class GlobalPerf extends Component {
  render() {
    const ins = this.props.insights; // I can't go deeper than that.

    console.log(ins.insights);

我无法访问对象中的值。我不能比this.props.insights更深入当我尝试this.props.insights.data时，它不起作用。有人可以帮我弄清楚吗？ Thx

Answer 1

this.setState({insights: resI.data});
console.log(this.state.insights.insights.data[0].values[1].value); //I Get 270. It working in the parent component

以上语句不起作用，因为setState是异步的，并且不会同步更新该值。可能显示旧状态值？

setState（）不会立即使this.state发生突变，但会创建一个挂起的状态转换。调用此方法后访问this.state可能会返回现有值。无法保证对setState的调用的同步操作，并且可能为提高性能而对调用进行批处理。

您可能在axios完成之前尝试访问props.insights

const ins = this.props.insights; // probably wait for the axios to complete the fetch before trying to access the value! write it as

console.log(ins && ins.insights); //will give insights once the component rerenders after the props change due to the state being updated in the parent after axios returns!