js以10的倍数向上取整

封装方法countTotal(),传参n为当前需要处理的值，base为向上取整的基数

countTotal(n,base) {
      const x = n % base
      return x > 0 ? n - x + base : n
    },

实例：

            <el-input-number
              v-model="diaObj.num"
              :min="1"
              size="medium"
              :step="goodCase?goodCase:1"
              @change="changeQuantity"
            ></el-input-number>
             //监听库存输入值的变化方法
            changeQuantity(value){
              if(this.goodCase){
                this.$nextTick(() => {
                  this.diaObj.num = this.countTotal(value,this.goodCase)
                });
              }else{
                this.diaObj.num = value
              }
            },