折线图设置线最大值为刻度最大值时再加处理均匀刻度值

max: function (value) {
                console.log("value", value.max)
                let n = (value.max + "").split(".")[0].length
                let pow = Math.pow(10, n - 1) // 10, 100, 1000,.....
                let floorNUm = Math.floor(value.max / pow) //1,2,3,4,5,.....
                let max = (floorNUm + 1) * pow
                return max ? max : 'dataMax'
            }