title: refs in reactjs Component empty
body: <p>I have a react-chartjs-2 element in my render function that I assign a ref to from React.createRef() but</p>
  
  <ol>
  <li>refs is empty</li>
  <li><p>the current property on my ref is null</p>
  
  <pre><code>import React, { Component } from 'react';
  const LineChart = require('react-chartjs-2').Line;
  
  class App extends Component {
    constructor(props) {
      super(props);
      this.chartRef = React.createRef();
      this.chartObject = null;
    }
  
    componentDidMount() {
      this.chartObject = this.chartRef.current.getContext('2d');
      this.chartObject.update();
    }
  
    render() {
  
      return ( 
        &lt;div className = "App"&gt;
          &lt;LineChart 
            data = {}
            width = {600}
            height = {250}
            ref = {this.chartRef}/&gt;
          &lt;/div&gt;
        );
      }
    }
  </code></pre></li>
  </ol>