code: function isTimeInRange (start, end) {
    let expStartTime = (new Date(start || Date.now())).getTime()
    let expEndTime = (new Date(end || '2099-01-01')).getTime()
    let nowTime = Date.now()
  
    // 如果实验生效时间配置错误
    if (!expStartTime || !expEndTime || expStartTime > expEndTime) {
      return false
    }
  
    return nowTime >= expStartTime && nowTime <= expEndTime
  }
docs: 判断是否是实验生效状态
  
  @param {Date|stirng|number} start 开始时间
  @param {Date|stirng|number} end 结束事件
  @returns {boolean} 当前时间是否生效的结果