vue中的自定义指令2.html

<!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>
    <script src="https://unpkg.com/vue@next"></script>
</head>
<style>
    .header {
        position: absolute;
    }
</style>

<body>
    <p>实现自定义属性 v-pos="数据" 使其数据可以改变dom元素的position距离</p>
    <p>v-abs:right=""  绑定组件属性赋值right 用binding.arg调用</p>
    <div id="root"></div>
    <script>
        const app = Vue.createApp({
            data() {
                return {
                    top: 100,
                    distance: 200
                }
            },

            template:
                `
            <div>
                <div v-pos="top" class="header">
                    <input /> 
                </div> 
                <div v-abs:right="distance" class="header">
                    <input /> 
                </div>  
            </div>
            `
        });

        // 这种写法等价于下面的写法 即当组件中只有mounted和updated时
        // app.directive('pos', () => {
        //     el.style.top = binding.value + 'px';
        // })

        app.directive('pos', {
            mounted(el, binding) {
                el.style.top = binding.value + 'px';
            },
            // 在改变数据时生效
            updated(el, binding) {
                el.style.top = binding.value + 'px';
            }

        });

        app.directive('abs', (el, binding) => {
            el.style[binding.arg] = (binding.value + 'px');
        })

        const vm = app.mount('#root');
    </script>

</body>

</html>