<template>
     <h2>当前计数为： {{counter}}</h2>
     <HelloWorld @add1="add1" @decre1="decre1"></HelloWorld>
</template>
<script setup>
  import { ref } from 'vue'
  import HelloWorld from './HelloWorld.vue'
  // 1、定义的属性
  const counter = ref(0)

  // 2、定义的方法
   const add1 = (payload) => {
     counter.value = payload
  }
  const decre1 = (payload) => {
     counter.value = payload
  }
</script>

<template>
    <div>
        <button @click="increment">+1</button>
        <button @click="decrement">-1</button>
        <div>
             <input type="text" v-model.number="num">
        </div>
    </div>
</template>
<script setup>
    import { ref, defineEmits } from 'vue'

    // 1、定义的属性
    const num = ref(0)

    // 2、定义发射给父组件的方法
    const emits = defineEmits(['add1', 'decre1'])

    // 3、定义新增和递减计数方法
    const increment = () => {
        num.value++
        emits('add1', num.value)
    }

    const decrement = () => {
        num.value--
        emits('decre1', num.value)
        
    }
</script>