title: update data which are fetched in componentDidMount
body: <p>I have two components:</p>
  
  <pre><code>class FloorView extends Component {
  constructor (props) {
      super(props);
      this.state = {
          dateBegin: moment(),
          dateEnd: '2018-09-30'
      }
      this.setDateBeginHandler = this.setDateBeginHandler.bind(this);
  }
  
  setDateBeginHandler(date) {
      this.setState({
          dateBegin: date
      });
  }
  
  render() {
      return (
          &lt;div className="FloorView"&gt;
              &lt;div className="Toolbar"&gt;
                  &lt;DatePicker2 selected={this.state.dateBegin} onChange={this.setDateBeginHandler} /&gt;
                  &lt;DatePicker className="dateBegin" /&gt;
                  &lt;DatePicker className="dateEnd" /&gt;
              &lt;/div&gt;
              &lt;Room dateBegin={this.state.dateBegin.format("YYYY-MM-DD")} dateEnd={this.state.dateEnd} /&gt;
          &lt;/div&gt;
      );
  }
  </code></pre>
  
  <p>}</p>
  
  <p>and</p>
  
  <pre><code>import React, { Component } from 'react';
  import Circle from './Circle/Circle';
  import './Room.css';
  
  class Room extends Component {
  setDesks(floor) {
      // fetch call which accesses this.props.dateBegin to fetch data
  }
  
  componentDidMount() {
      this.setDesks(1);
  }
  
  render() {
      return (
          &lt;div&gt;
          ....
          &lt;/div&gt;
      );
  }
  </code></pre>
  
  <p>}</p>
  
  <p>If in FloorView the handler setDateBeginHandler() is triggered, the property 'dateBegin' in Room component is changed. How can I call my setDesks() to fetch data again? Until now the change has no impact.</p>
  
  <p>Thanks.</p>