vue的计算属性computed
任何复杂逻辑，在vue里都应当使用计算属性computed，计算属性是方法而不是属性，我们可以将同一函数定义为一个方法而不是一个计算属性。两种方式的最终结果确实是完全相同的。然而，不同的是计算属性是基于它们的响应式依赖进行缓存的。只在相关响应式依赖发生改变时它们才会重新求值。下面是一个小demo，有助于大家理解和运用computed属性
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script src="../node_modules/vue/dist/vue.js"></script>
<style>
li{list-style: none;}
.active{background:red;}
</style>
</head>
<body>
<div id="app">
<audio :src="getCurrentsong" autoplay="autoplay" controls="controls"></audio>
<ul>
<li v-for="(song,index) in musicData" :class="{active:index==currentIndex}" @click="clickHandler(index)">
<h2>{{song.id}}--{{song.name}}</h2>
<h3>{{song.songSrc}}</h3>
</li>
</ul>
</div>
<script type="text/javascript">
var musicData = [
{
id: 1,
name: "I believe",
songSrc: "../music/I believe.mp3",
author: "杨培安"
},
{
id: 2,
name: "一百万个可能.mp3",
songSrc: "../music/一百万个可能.mp3",
author: "Skot Suyama"
},
{
id: 3,
name: "I believe",
songSrc: "../music/I believe.mp3",
author: "杨培安"
}
];
new Vue({
el:"#app",
data(){
return{
musicData,
currentIndex:0
}
},
methods:{
clickHandler(index){
this.currentIndex=index;
}
},
computed:{
getCurrentsong:function(){
return this.musicData[this.currentIndex].songSrc
}
}
})
</script>
</body>
</html>