App.vue
CompOne.vue
main.js
 
<template>
  <h2>Example v-model Directive</h2>
  <p>App.vue 'text' property: "<pre>{{ text }}</pre>"</p>
  <button v-on:click="this.text = 'Hello!'">text='Hello!'</button>
  <comp-one v-model="text"/>
</template>

<script>
export default {
  data() {
    return {
      text: 'Say Cheese'
    }
  }
}
</script>

<style>
pre {
  display: inline;
  background-color: yellow;
}
</style>                  
<template>
  <div>
    <h3>Component</h3>
    <p>Two-way binding on component with v-model:</p>
    <ol>
      <li>The component can update the 'text' property (using text field).</li>
      <li>The component gets updated when the 'text' property is changed (using button).</li>
    </ol>
    <input
      :value="modelValue"
      @input="$emit('update:modelValue', $event.target.value)"
    />
  </div>
</template>

<script>
  export default {
    props: ['modelValue'],
    emits: ['update:modelValue']
  }
</script>

<style scoped>
div {
  border: solid black 1px;
  padding: 10px;
  margin: 20px 0;
  max-width: 600px;
}
</style>                  
import { createApp } from 'vue'

import App from './App.vue'
import CompOne from './components/CompOne.vue'

const app = createApp(App)
app.component('comp-one', CompOne)
app.mount('#app')
                  
http://localhost:5173/