/src/utils/validate.js

// 银行卡号校验
export let bankNumberValid = (rule, value, callback) => {
  if (value) {
    if (!Number.isInteger(+value)) {
      callback(new Error('银行卡号必须全为数字'))
    } else if (value.trim().length < 16 || value.trim().length > 19) {
      callback(new Error('银行卡号长度必须在16到19之间'))
    } else {
      callback()
    }
  } else if (rule.required) {
    callback(new Error(rule.msg))
  } else {
    callback()
  }
}

使用：

xx.vue

<script>
import { bankNumberValid, phoneNumberValid } from '@/utils/validate_provider'

      // 表单校验
      rules: {
        bankNumber: [
          { required: false, trigger: "blur", validator: bankNumberValid }
        ],