YYYYMMDDhhmmss转换成YYYY-MM-DD hh:mm:ss 或其他样式

changeTime (val) {
  const pattern = /^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})$/
  try {
    return val.replace(pattern, ‘$1-$2-$3 $4:$5:$6‘)
  } catch (error) {
    return ‘--‘
  }
}