计算属性全选反选

最新推荐文章于 2023-04-12 16:09:42 发布

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最新推荐文章于 2023-04-12 16:09:42 发布

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文章标签： javascript vue.js 前端

本文链接：https://blog.youkuaiyun.com/wangyangzxc123/article/details/127729837

版权

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <input type="checkbox" v-model="flag">全选
        <ul>
            <li v-for="(item, index) in list" :key="index"><input type="checkbox" name="" id="" v-model="item.show">{{item.name}}</li>
        </ul>
    </div>
</body>
</html>
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<script>
    const obj = new Vue({
        el: '#app',
        data: {
            list: [
                { show: false, name: 'zs' },
                { show: true, name: 'ls'},
                { show: false, name: '大西瓜'},
                { show: true, name: '夏普'}
            ]
        },
        methods: {
        },
        computed: { // 计算属性比事件好的优势在于计算属性有缓存
            flag: {
                get() {
                    let shows = null
                    let obj = []
                    this.list.forEach(item => {
                        if(item.show === true) {
                            obj.push(item) // 将list中的每一项为true添加到新数组中, 只有所有都为true的情况下说明list的每一项都为true了,即obj的长度等于list的长度
                        }
                    })
                    if(obj.length === this.list.length) {
                        shows = true
                    } else {
                        shows = false
                    }
                    return shows
                },
                set(value) {
                    this.list.forEach(item => {
                        item.show = value
                    })
                }
            }
        }
    })
</script>