arrays - react this.setState 不更新数组状态变量

Question

有很多关于涉及数组的 react 状态更新的帖子，但它们似乎都没有解决我的问题。

我正在使用 FullCalendar.io 组件，该组件接受事件数组作为来自父组件的 prop，并填充日历单元格。我尝试基于 nextProps.cal_events 设置状态 'cal_events_state'，但由于某种原因 cal_event_state 被设置为 [](显然初始状态值被覆盖)。

我错过了什么？

import React from 'react';
import ReactDOM from 'react-dom';
var $ = require ('jquery')

var Calendar = React.createClass ({
  render: function() {
    return <div id="calendar"></div>;
  },

  getInitialState: function() {
      return {
        cal_events_state: [{"due": "201505", "title": "Production"}]
        , test_state: 11
      }
  },

componentDidMount: function() {
var self = this;
const var_cal_events = this.props.cal_events; //This prop is blank at this point because ajax hasn't returned an array yet.
$('#calendar').fullCalendar({
        header: {
            left: 'prev,next today',
            center: 'title',
            right: 'month,agendaWeek,agendaDay'
        },
        editable: true,
        events: var_cal_events;
    })
  },
  componentWillReceiveProps: function(nextProps) {
    var self = this;
    var var_cal_events = nextProps.cal_events;  // after receiving the ajax fetch payload, this has some event tasks.

    this.setState({
      cal_events_state: var_cal_events, // This doesn't update state with the newly received payload
      test_state: 22            // This updates state
})
$('#calendar').fullCalendar({
  events: var_cal_events

})

$('#calendar').fullCalendar('refetchEvents');

},


});

Answer 1

事实证明“setState”确实更新了状态变量，但我没有意识到直到函数执行完成(即直到你的代码退出函数 block )它才这样做。我正在检查this.state.variable 就在 setState 语句之后，这让它看起来像变量没有更新。