watch監聽對象的屬性

時間 2019-11-19

標籤 watch 監聽對象屬性简体版

原文原文鏈接

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <meta name="author" content="楊欣">
    <title></title>
    <style>
        html,
        body {
            margin: 0;
            padding: 0
        }
    </style>
    <script src="https://cdn.bootcss.com/vue/2.6.10/vue.min.js"></script>
</head>

<body>
    <div id="app">{{obj.name}}</div>
    <script>
        let app = new Vue({
            el: "#app",
            data: {
                obj: {
                    name: 'yx'
                }
            },
            computed: {
                //1.把要監聽的屬性做爲計算屬性
                // name() {
                //     return this.obj.name
                // }
            },
            watch: {
                // name(newVal, oldVal) {
                //     console.log(newVal, oldVal)
                // }

                // 2.監聽obj，加上deep
                obj: {
                    handler(newVal, oldVal) {
                        console.log(newVal, oldVal)
                    },
                    deep: true
                }
            },
        })
    </script>
</body>

</html>

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