react hooks使用echarts5

在react hooks5使用echarts5有可能会抛出 警告

使用useRef来解决

function Demo() {
 const dom = useRef();
  useEffect(() => {
    if(!dom.current) {
      dom.current = echarts.init(document.getElementById('chart'));
    }
    console.log(dom.current, 'current');
    dom.current.setOption({
      xAxis: {
        type: 'category',
        data: ['a', 'b', 'c', 'd']
      },
      yAxis: {
        type: 'value'
      },
      series: [{
        type: 'line',
        data: [10, 12, 6, 9]
      }]
    })
  }, [dom]);

  return (
    <div>
      <span>count = {count}</span>
      <Button onClick={handlerAdd}>add</Button>
      <div  style={{width: 300, height: 200}}></div>
    </div>
  );
}