How to use v-model on component in vue 3 script setup

Question

I want to add a v-model on a component but I got this warning:

[Vue warn]: Component emitted event "input" but it is neither declared in the emits option nor as an "onInput" prop.

Here is my code:

// Parent.vue
<template>
  <h2>V-Model Parent</h2>
  <Child v-model="name" label="Name" />
  <p>{{ name }}</p>
</template>

<script setup>
import { ref } from 'vue'
import Child from './Child.vue'

const name = ref('')
</script>

// Child.vue
<template>
  <input
    class="input"
    type="text"
    :placeholder="props.label"
    :value="props.value"
    v-on:input="updateValue($event.target.value)"
  />
</template>

<script setup>
import { defineProps, defineEmit } from 'vue'
const props = defineProps({
  label: String,
  value: String
})
const emit = defineEmit('input')

function updateValue(value) {
  emit('input', value)
}
</script>

I was trying to reproduce this tutorial but I'am stuck and got no idea what I am missing.

I want to display {{ name }} in the Parent.vue component. Do you got an idea how to solve this?

Answer 1

In vue 3 value prop has been changed to modelValue and the emitted event input to update:modelValue:

// Child.vue
<template>
  <input
    class="input"
    type="text"
    :placeholder="props.label"
    :value="props.modelValue"
    v-on:input="updateValue($event.target.value)"
  />
</template>

<script setup>

const props = defineProps({
  modelValue: String
})

const emit = defineEmits(['update:modelValue'])

function updateValue(value) {
  emit('update:modelValue', value)
}
</script>

Answer 2

I like to use with computed as well

<template>
  <div>
    <input v-model="model">
  </div>
</template>

<script setup>
import { computed } from 'vue'

const props = defineProps({
  modelValue: {
    type: [String, Number],
    default: ''
  }
})

const emit = defineEmits(['update:modelValue'])

const model = computed({
  get () {
    return props.modelValue
  },

  set (value) {
    return emit('update:modelValue', value)
  }
})
</script>