vue如何彻底清除echarts上保留的数据

<template>
 <div class="echarts">
 <IEcharts :option="bar" :loading="loading" @ready="onReady" @click="onClick"></IEcharts>
 <button @click="doRandom">Random</button>
 </div>
</template>
 
<script type="text/babel">
 import IEcharts from 'vue-echarts-v3/src/full.js';
 export default {
 name: 'view',
 components: {
  IEcharts
 },
 props: {
 },
 data: () => ({
  loading: true,
  bar: {
  title: {
   text: 'ECharts Hello World'
  },
  tooltip: {},
  xAxis: {
   data: ['Shirt', 'Sweater', 'Chiffon Shirt', 'Pants', 'High Heels', 'Socks']
  },
  yAxis: {},
  series: [{
   name: 'Sales',
   type: 'bar',
   data: [5, 20, 36, 10, 10, 20]
  }]
  }
 }),
 methods: {
  doRandom() {
  const that = this;
  let data = [];
  for (let i = 0, min = 5, max = 99; i < 6; i++) {
   data.push(Math.floor(Math.random() * (max + 1 - min) + min));
  }
  that.loading = !that.loading;
  that.bar.series[0].data = data;
  },
  onReady(instance) {
  console.log(instance);
  },
  onClick(event, instance, echarts) {
  console.log(arguments);
  }
 }
 };
</script>
 
<style scoped>
 .echarts {
 width: 400px;
 height: 400px;
 }
</style>