ECharts y轴坐标均分，且最小值不出现小数

 yAxis: {
 	max:value => {
        if (value.max < 10) {
            return 10;
        }
        let max = value.max;
        let val = max / 5;
        const round = true;
        const exponent = Math.floor(Math.log(val) / Math.LN10);
        const exp10 = Math.pow(10, exponent);
        const f = val / exp10; // 1 <= f < 10
        let nf;
        if (round) {
          if (f < 1.5) { nf = 1; }
          else if (f < 2.5) { nf = 2; }
          else if (f < 4) { nf = 3; }
          else if (f < 7) { nf = 5; }
          else { nf = 10; }
        } else {
          if (f < 1) { nf = 1; }
          else if (f < 2) { nf = 2; }
          else if (f < 3) { nf = 3; }
          else if (f < 5) { nf = 5; }
          else { nf = 10; }
        }
        val = nf * exp10;
        return val*5;
    },
 }