function isEmpty(val) {
  return typeof val === 'undefined' || val === '' || val === null
}

function formateDate(datetime) {
  if (isEmpty(datetime)) {
    return ''
  }
  var dayCode = 24 * 60 * 60 * 1000
  datetime = datetime.replace(getRegExp('/\s/g', 'g'), '')
  var date = getDate(datetime.trim())
  var today = getDate()
  var yestoday = getDate(getDate().getTime() - dayCode)
  var week = ''
  if (date.getFullYear() === today.getFullYear() && date.getMonth() === today.getMonth() && date.getDate() === today.getDate()) {
    week = '今天 ' + datetime.substring(10)
  } else if (date.getFullYear() === yestoday.getFullYear() && date.getMonth() === yestoday.getMonth() && date.getDate() === yestoday.getDate()) {
    week = '昨天 ' + datetime.substring(10)
  }
  if (isEmpty(week)) {
    return datetime
  }
  return week
}
 
module.exports = {
  formateDate: formateDate
}