折线图距离两侧会有空白，想要将空白去除
通过boundaryGap控制
类目轴中boundaryGap可以配置为true和false。默认为true

将boundaryGap:设为 false就可以实现两侧空白去除

drawLine () {
      window.addEventListener('resize', this.drawLine)
      let myChart = this.$echarts.init(this.$refs.echarts)
      var data = {
        city: ['2021.08.10',
          '2021.08.11',
          '2021.08.12',
          '2021.08.13',
          '2021.08.14',
          '2021.08.15',
          '2021.08.16',
          '2021.08.17',
          '2021.08.18',
          '2021.08.19',
          '2021.08.20',
          '2021.08.21',
          '2021.08.22',
        ],
        num: [40, 50, 60, 40, 50, 40, 50, 60, 45, 45, 50, 55, 55]
      }
      var option = {
        tooltip: {
          trigger: 'axis',
          axisPointer: { // 坐标轴指示器，坐标轴触发有效
            type: 'shadow' // 默认为直线，可选为：'line' | 'shadow'
          }
        },
        grid: {
          top: '5%',
          left: '5%',
          right: '5%',
          bottom: '28%'
        },
        xAxis: [{
          type: 'category',
          boundaryGap: false,
          axisLine: {
            show: true,
            lineStyle: {
              color: '#263F74'
            },
          },
          axisLabel: {
            textStyle: {
              color: '#5F7FA0',
              margin: 0,
            },
            interval: 0,
            rotate: 40,
          },
          axisTick: {
            show: false,
          },
          data: data.city
        }],
        yAxis: [{
          splitLine: {
            show: true,
            lineStyle: {
              color: '#092b5d'
            },
          },
          axisLine: {
            show: true,
            lineStyle: {
              color: '#263F74'
            }

          },
          axisLabel: {
            show: true,
            textStyle: {
              color: '#5F7FA0'
            },
          },
          axisTick: {
            show: false,
          },
        }],
        series: [{
          name: '30日内接入车辆数',
          type: 'line',
          symbol: 'circle', // 默认是空心圆（中间是白色的），改成实心圆
          showAllSymbol: true,
          symbolSize: 8,
          lineStyle: {
            normal: {
              color: 'rgba(245, 180, 9, 1)', // 线条颜色
            },
          },
          itemStyle: {
            color: 'rgba(245, 180, 9, 1)',
            borderColor: 'rgba(245, 180, 9, 1)',
            borderWidth: 3
          },
          label: {
            normal: {
              show: false,
              position: 'top',
              rich: {
                a: {
                  color: '#fff',
                  align: 'center',
                },
              }
            }
          },
          tooltip: {
            show: true
          },
          areaStyle: {
            normal: {
              color: new this.$echarts.graphic.LinearGradient(0, 0, 0, 1, [{
                offset: 0,
                color: 'rgba(245, 180, 9, 0.3)'
              },
                {
                  offset: 1,
                  color: 'rgba(0, 156, 255, 0)'
                }
              ], false),
            }
          },
          data: data.num
        }]
      }
      myChart.clear()
      myChart.resize()
      myChart.setOption(option)
    },