Vue2与vue3 写法对照

vue3写法

<template>
  <div>
    <input placeholder="请输入" style="color: red; font-size: 80px;" v-model="inputValue" />
    <button @click="handleSubmit">提交</button>
  </div>
</template>
<script setup>
	 import { ref } from 'vue';
     const inputValue = ref('');
	 function handleSubmit() {
		  if (inputValue.value === '') {
			alert('请输入内容')
		  } else {
			alert('已输入')
		  }
	 }
</script>

vue2写法

<template>
  <div>
    <input v-model="inputValue" />
    <button @click="handleSubmit">提交</button>
  </div>
</template>
<script>
export default {
  data() {
    return {
      inputValue: ''
    }
  },
  methods: {
    handleSubmit() {
      if (this.inputValue === '') {
        alert('请输入内容')
      } else {
        // do something...
      }
    }
  }
}
</script>