• • 我试图用一个简单的空字符串输入验证来实现提交按钮逻辑，但是在点击按钮之后，整个窗口都变空了。虽然符合if语句，但需要显示一个块。

https://codesandbox.io/s/intelligent-jasper-teh1im?file=/src/components/Button.vue* *

<template>
  <button class="btn" @click="submit">Submit</button>
</template>

<script>
export default {
  inject: [
    "firstName",
    "lastName",
    "paymentAmount",
    "accountNumber",
    "isFinalStep",
  ],
  data() {
    return {
      firstName: this.firstName,
      lastName: this.lastName,
      paymentAmount: this.paymentAmount,
      accountNumber: this.accountNumber,
    };
  },
  methods: {
    submit() {
      if (
        !this.firstName &&
        !this.lastName &&
        !this.paymentAmount &&
        !this.accountNumber
      ) {
        this.isFinalStep();
      } else {
        alert("please fill the required fields");
      }
    },
  },
};