title: Chart not updating after data change in react chartjs
body: <p>I made a line chart with react chartjs. The chart is working perfectly fine but when I try to update the chart, it didn't get updated. Although I am able to change the data of the chart. Please help.
  I try to update the chart on the legend click. I go through some tutorials and see like update function will help me. But when I try the update function with my line, it shows an error with 'undefined update function'.</p>
  
  <pre><code>
  import React from 'react';
  
  import {Line} from 'react-chartjs-2';
  
  
  const checkinsData={
      labels:['4 P.M','5 P.M','6 P.M','7 P.M','8 P.M','9 P.M','10 P.M','11 P.M','12 A.M','1 A.M','2 A.M','3 A.M','4 A.M'],
      datasets:[
          {
          label:"Day",
          backgroundColor:"blue",
          borderColor:'#333',
          borderWidth:2,
          lineTension:0.1,
          fill:true,
          data:[4,5,6,7,8,9,10,11,12,1,2,3,4]
  
          }
  
  
      ]
  }
  
  
  
  class CheckinGraph extends React.Component{
      constructor(props)
      {
          super(props)
          this.state={
  
          }
      }
  
      legendClick=function() {
          console.log("Legend click"+ checkinsData.labels);
          checkinsData.datasets.data=[100,120,200,25,56,78,80,90,70,100];
      }
      render()
      {
          return(
              &lt;div className="col-md-12  default-shadow bg-white pd-30-0 border-radius-10 align-center"&gt;
              &lt;Line
              redraw
          data={checkinsData}
          options={
              {
                  title:{
                      text:'Total Check-ins',
                      fontSize:20,
                      display:true
                  },
                  legend:{
                      display:true,
                      position:'top',
                      onClick:this.legendClick
                  }
              }
          }
          /&gt;
              &lt;/div&gt;
  
          )
      }
  }
  
  export default CheckinGraph;
  
  
  </code></pre>