b站 vue.js视频中的案例成果如下：
主要功能：
1."+1"和"-1"控制下面的数字
2.减到0时，"-1"按钮消失
3.利用子传父的通信实现
代码如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>test</title>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app">
<child @fa-add = "chage" @fa-minus = "chage"></child>
<h2>当前次数：{{num}}</h2>
</div>
<template id="cpn">
<div>
<button @click = "add">+1</button>
<button @click = "minus" :disabled = "number <= 0">-1</button>
</div>
</template>
<script>
var app= new Vue({
el: '#app',
data: {
num:0
},
methods: {
chage(number){
this.num = number
}
},
components:{
'child':{
template:"#cpn",
data() {
return {
number:0
}
},
methods: {
add(){
this.number++;
this.$emit('fa-add',this.number)
},
minus(){
this.number--;
this.$emit('fa-minus',this.number)
}
}
}
}
})
</script>
</body>
</html>