<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>小黑的书架</title>
</head>
<body>
<div id="app">
<h3>小黑的书架</h3>
<input type="text" v-model="todoName" placeholder="请输入"><button @click="add">添加</button>
<ul>
<li v-for="(item,index) in bookslist" :key="item.id">
<span>{{index+1}}</span>
<span>{{item.name}}</span>
<span>{{item.author}}</span>
<!--注册点击事件，通过id进行删除数组中的对应项-->
<button @click="del(item.id)">删除</button>
</li>
<button v-show="bookslist.length>0">合计：{{bookslist.length}}</button>
<button v-show="bookslist.length>0" @click="clear">清空</button>
</ul>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
const app = new Vue({
el:'#app',
data:{
bookslist:[
{id:1,name:'《红梦楼1》',author:'曹雪芹'},
{id:2,name:'《红梦楼2》',author:'曹雪芹'},
{id:3,name:'《红梦楼3》',author:'曹雪芹'},
{id:4,name:'《红梦楼4》',author:'曹雪芹'}
],
todoName:''
},
methods:{
del(id){
// this.bookslist
//通过id进行删除数组中的对应项->filter(不会改变原数组)
//filter:根据条件，保留满足条件的对应项，得到一个新数组
this.bookslist=this.bookslist.filter(item=>item.id!==id)
},
add(){
if(this.todoName.trim()==''){
alert('请输入任务名称')
return;
}
this.bookslist.unshift({
id:+ new Date(),
name:this.todoName
})
this.todoName='';
},
clear(){
this.bookslist=[];
}
}
})
//data中的数据，是会被添加到实列上
//1.访问数据 实列.属性名
//2.修改数据 实列.属性名=新值
</script>
</body>
</html>
