VUE-计算属性

computed/methods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重新求值。这就意味着只要 message 还没有发生改变，多次访问 reversedMessage 计算属性会立即返回之前的计算结果，而不必再次执行函数。

computed/methods

v0.计算属性computed/methods</div>

<hr />

<div>

</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>

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>

View Code

REF:

http://www.runoob.com/vue2/vue-computed.html

https://cn.vuejs.org/v2/guide/computed.html

posted @ 2017-12-27 23:55 zhen-Android 阅读(320) 评论(0) 编辑收藏举报

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VUE-计算属性

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