/**
 *格式化時(shí)間
 *yyyy-MM-dd hh:mm:ss
 */
formatDate(time, fmt) {
  if (time === undefined || '') {
    return
  }
  const date = new Date(time)
  if (/(y+)/.test(fmt)) {
    fmt = fmt.replace(RegExp.$1, (date.getFullYear() + '').substr(4 - RegExp.$1.length))
  }
  const o = {
    'M+': date.getMonth() + 1,
    'd+': date.getDate(),
    'h+': date.getHours(),
    'm+': date.getMinutes(),
    's+': date.getSeconds()
  }
  for (const k in o) {
    if (new RegExp(`(${k})`).test(fmt)) {
      const str = o[k] + ''
      fmt = fmt.replace(RegExp.$1, RegExp.$1.length === 1 ? str : padLeftZero(str))
    }
  }
  return fmt
}
    const now = new Date();
      const fmt = 'yyyy-MM-dd 00:00:00';
      // 當(dāng)日開(kāi)始時(shí)間
      const dayStart = formatDate(now, fmt);
      // 當(dāng)前時(shí)間
      const dayNow = formatDate(now, 'yyyy-MM-dd hh:mm:ss');
      // 當(dāng)月開(kāi)始時(shí)間
      const m = now.setDate(1);
      const monthStart = formatDate(m, fmt);
      // 當(dāng)年開(kāi)始時(shí)間
      const y = now.setMonth(0);
      const yearStart = formatDate(y, fmt);
      console.log(dayStart);
      console.log(dayNow);
      console.log(monthStart);
      console.log(yearStart);