<div id="myChart"></div>
data(){
    myChart:null,
    echarts_option1:{},
},
methods:{
    setEcharts() {
          let myChart = document.getElementById("myChart");
          myChart.style.width = window.innerWidth - 290 + "px";  //初始化echarts图表宽度
          this.myChart = this.$echarts.init(myChart);
          this.myChart.setOption(this.echarts_option1);
          let self = this;
          window.addEventListener("resize", () => {  // 通过resize方法来重设图表宽度
              let myChart = document.getElementById("myChart");
              myChart.style.width = window.innerWidth - 290 + "px";
              self.myChart.resize(); 
          });
},
 mounted() {
    this.setEcharts();
},

<style>
#myChart {
  width: 100%;
  height: 320px;
}
</style>