代码如下：

<el-date-picker
      v-model="value"
      type="datetimerange"
      start-placeholder="Start Date"
      end-placeholder="End Date"
      :default-time="defaultTime"
/>

const defaultTime: [Date, Date] = [
  new Date(2000, 1, 1, 12, 0, 0),
  new Date(2000, 2, 1, 8, 0, 0),
] // '12:00:00', '08:00:00'

获取当前月的起始 结束日期

const getCurrentDate = ():Array<string> =>{
  let currentTimeRange = [] as Array<string>;
  const currentDate = new Date();

  // 获取当前月份
  const currentMonth = currentDate.getMonth() + 1; // 月份从 0 开始，所以需要加 1

  // 获取当前月份的起始时间
  const startTime = `${currentDate.getFullYear()}-${currentMonth
    .toString()
    .padStart(2, '0')}-01 00:00:00`;

  // 获取当前月份的终止时间
  const lastDay = new Date(
    currentDate.getFullYear(),
    currentMonth,
    0
  ).getDate();

  const endTime = `${currentDate.getFullYear()}-${currentMonth
    .toString()
    .padStart(2, '0')}-${lastDay.toString().padStart(2, '0')} 23:59:59`;
  currentTimeRange = [startTime,endTime]
  
  //返回当前月的起始 结束日期
  return currentTimeRange
}