多个时间段 合并

//四个时间段的拼接
joinDayTime(t1, t2, t3, t4) {
  let n = '';
  if(this.dateToString(t1)) n += this.dateToString(t1) + ','
  if(this.dateToString(t2)) n += this.dateToString(t2) + ','
  if(this.dateToString(t3)) n += this.dateToString(t3) + ','
  if(this.dateToString(t4)) n += this.dateToString(t4) + ','
  if(n.length) {
    let m = this.joinTime(n.substr(0, n.length - 1))
    m.length = 4
    return  m.join(',')
  }else {
    return null
  }
},
//合并时间方法 思路 转换为数字区间，判断大小在转换为 时间
joinTime(value) {
  //数间排序
  var merge = function (intervals) {
    if (intervals.length === 0) return []
    let res = []
    intervals.sort((a, b) => a[0] - b[0]) //数组首位排序函数sort
    let candidate = intervals[0] //排序后选择第一个数组  (临时空间)
    for (let i = 1; i < intervals.length; i++) {
      let cur = intervals[i] //从第二个开始取cur
      if (candidate[1] >= cur[0]) { // 有重合 能合并
        candidate[1] = Math.max(cur[1], candidate[1]) // 左端不变 右端取大的
      } else { // 不重合 不能合并
        res.push(candidate)
        candidate = cur //把cur放进去临时控件
      }
    }
    res.push(candidate)
    return res
  };
  //拼成统一的四位数
  let formatZero = function(num) {
    if(String(num).length > 4) return num;
    return (Array(4).join(0) + num).slice(-4);
  }
  // 数转换为时间
  var getTime = function (num) {
    return formatZero(num).slice(0, 2) + ':' + formatZero(num).slice(2);
  }
  var reg=/:/g;
  let time = value.toString().split(',')
  for (var i = 0; i < time.length; i++) {
    time[i] = time[i].replace(reg,'').split('-')
    for (var j = 0; j < time[i].length; j++) {
      time[i][j] = parseInt(time[i][j])
    }
  }
  let newdate = merge(time)
  for (let k = 0; k < newdate.length; k++) {
    newdate[k] = getTime(newdate[k][0]) + "-" + getTime(newdate[k][1])
  }
  return newdate
},