const validateBackAccount = (rule, value, callback) => {
  //return value === value.replace(/[^[a-z0-9A-Z]+$/g, '')
  //return ''  === value.replace(/[a-z0-9A-Z]+/g, '')
  let pattern = /[^[a-z0-9A-Z]+/g
  return !pattern.test(value)
}
const initFormRules = ref({
  backAccount: [
    { required: true, message: '请输入账号', trigger: 'blur' },
    { min: 5, max: 20, message: '账号长度为5-20位', trigger: 'blur' },
    { validator: validateBackAccount, message: '仅支持英文字母与数字', trigger: 'blur' },
  ],
})