Vue的data值必须是函数返回

data值必须要是函数返回,这样才能使组件在多次调用的时候 改变其中的data其他的不受到影响

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>返回data必须是函数</title>
    <!--引入vue -->
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

</head>
<body>

<div id="app">
    <psd></psd>
    <psd></psd>
    <psd></psd>
    <psd></psd>
</div>

<template id="myTem">
    <div>
        <button @click="counter ++">data值互不影响 : {{counter}}</button>
    </div>
</template>

<script>
    let Pro = Vue.extend({
        template: "#myTem",
        data(){
            return {
                counter : 0
            }
        }
    });

    Vue.component('psd', Pro);

    new Vue({
        el: "#app",
    })


</script>
</body>
</html>

 

如果data是一个对象的话 ,那么调用组件中的data是唯一的,受到改变会相互影响

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>返回data必须是函数</title>
    <!--引入vue -->
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

</head>
<body>

<div id="app">
    <psd></psd>
    <psd></psd>
    <psd></psd>
    <psd></psd>
</div>

<template id="myTem">
    <div>
        <button @click="counter ++">data值互不影响 : {{counter}}</button>
    </div>
</template>

<script>

    var data = {
        counter : 0
    }

    let Pro = Vue.extend({
        template: "#myTem",
        data(){
            return data
        }
    });

    Vue.component('psd', Pro);

    new Vue({
        el: "#app",
    })


</script>
</body>
</html>