computed/methods两种方式的最终结果确实是彻底相同的。然而，不一样的是计算属性是基于它们的依赖进行缓存的。计算属性只有在它的相关依赖发生改变时才会从新求值。这就意味着只要 message 尚未发生改变，屡次访问 reversedMessage 计算属性会当即返回以前的计算结果，而没必要再次执行函数。javascript
computed/methodshtml
| <!-- 计算属性computed/methods -->vue <div style="height: 250px;background: #CCC;margin: 5px;">java <div style="font-size: 20px;">缓存 v0.计算属性computed/methods</div>app <hr />ide <div>函数 <div>ui <p>{{msg}}</p>this </div> <div> <p>反转字符串：{{reverseMsg}}</p> </div> <div> <p>反转字符串：{{reverseMsg1()}}</p> </div> <div> <p>Setter/Getter：{{fullName}}</p> </div> </div> </div> |
| <!-- 计算属性computed/methods --> <script> var vm = new Vue({ el: "#appVue", data: { msg: "ABCDEFG", msg1: "abcdefg", chPart: "Key", digPart: "123456", }, computed: { reverseMsg: function() { return this.msg.split('').reverse().join('') }, fullName: { get: function() { return this.chPart + this.digPart; }, set: function(newVar) { this.chPart = newVar; this.digPart = newVar; } } }, methods: { reverseMsg1: function() { return this.msg1.split('').reverse().join('') } } }) console.log(vm.reverseMsg); vm.msg = "AAABBB"; console.log(vm.reverseMsg); vm.fullName = "Null"; </script> |
<!DOCTYPE html>
<html style="height: 100%;">
<head>
<meta charset="UTF-8">
<script type="text/javascript" src="../lib/vue.v2.5.12.js"></script>
<title>v-xxx</title>
</head>
<body style="height: 100%;">
<style>
.style0 {
font-size: 25px;
color: green;
}
.style1 {
background: gold;
}
</style>
<!--
VUE-计算属性
REF:
http://www.runoob.com/vue2/vue-computed.html
https://cn.vuejs.org/v2/guide/computed.html
-->
<div id="appVue">
<!-- 计算属性computed/methods -->
<div style="height: 250px;background: #CCC;margin: 5px;">
<div style="font-size: 20px;">
v0.计算属性computed/methods</div>
<hr />
<div>
<div>
<p>{{msg}}</p>
</div>
<div>
<p>反转字符串：{{reverseMsg}}</p>
</div>
<div>
<p>反转字符串：{{reverseMsg1()}}</p>
</div>
<div>
<p>Setter/Getter：{{fullName}}</p>
</div>
</div>
</div>
</div>
<script>
var vm = new Vue({
el: "#appVue",
data: {
msg: "ABCDEFG",
msg1: "abcdefg",
chPart: "Key",
digPart: "123456",
},
computed: {
reverseMsg: function() {
return this.msg.split('').reverse().join('')
},
fullName: {
get: function() {
return this.chPart + this.digPart;
},
set: function(newVar) {
this.chPart = newVar;
this.digPart = newVar;
}
}
},
methods: {
reverseMsg1: function() {
return this.msg1.split('').reverse().join('')
}
}
})
console.log(vm.reverseMsg);
vm.msg = "AAABBB";
console.log(vm.reverseMsg);
vm.fullName = "Null";
</script>
</body>
</html>
REF:
http://www.runoob.com/vue2/vue-computed.html
https://cn.vuejs.org/v2/guide/computed.html