Vue(10-20)

news2024/9/25 3:18:49

1Vue赋值方式

Object.defineProperty

<!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>
<script src="./js/vue.js"></script>
<body>
    <script>
        let person = {
            name:'tony teacher',
            sex:'male',
            //age:19
        }

        Object.defineProperty(person,'age',{
            value:19,
            enumerable:true, //可以枚举
            writable:true,  //可以被修改
            configurable:true,  //可以被删除
        })
        console.log(person)
    </script>
</body>
</html>

一般赋值方式一旦number变化不会同步到age

<!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>
<script src="./js/vue.js"></script>
<body>
    <script>
        let number = 18
        let person = {
            name:'tony teacher',
            sex:'male',
            age:number
        }

        
        console.log(person)
    </script>
</body>
</html>

getter实现常态化赋值

<!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>
<script src="./js/vue.js"></script>
<body>
    <script>
        let number = 10
        let person = {
            name:'tony teacher',
            sex:'male',
            
        }
        
        Object.defineProperty(person,'age',{
            get:function(){
            return number
        }
        })
        
        console.log(person)
    </script>
</body>
</html>

result
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2数据代理

通过一个对象代理另一个对象属性的操作（读写）

<!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="./js/vue.js"></script>
</head>
<body>
    <script>
        let obj1 = {x:100}
        let obj2 = {y:200}

        Object.defineProperty(obj2,'x',{
            get(){
                return obj1.x
            },
            set(value){
                obj1.x=value
            }
        })
    </script>
</body>
</html>

在这里插入图片描述

3Vue中的数据代理

Vue数据代理示意图：
在这里插入图片描述

<!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="./js/vue.js"></script>
</head>
<body>
    <div id="root">
        <h2>school:{{name}}</h2>
        <h2>addreee:{{address}}</h2>
    </div>
    <script>
       const vm = new Vue({
        el:'#root',
        data:{
            name:'某硅谷',
            address:'某科技园'
        }
       })
    </script>
</body>
</html>

conclude:
1vue数据代理通过vm代理data对象属性的读写操作
2代理好处：方便操作data里面的数据

4事件处理(需要重试)

methods

<!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="./js/vue.js"></script>
</head>
<body>
    <div id="root">
        <h2>欢迎来到{{name}},welcom</h2>
        <button v-on:click=showInfo()>电击我,告诉你情报是什么</button>
    </div>
    <script>
        new Vue({
            el:'#root',
            data:{
                name:'某硅谷'
            },
            method:{
                showInfo(){
                    alert('什么都没有')
                    console.log(event.target.innerText)
                    console.log(this)//显示vm
                }
            }
        })
    </script>
</body>
    

</html>

v-on: <==> @

在这里插入图片描述

5事件修饰符

<!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>事件的基本用法</title>
    <script src="../js/vue.js"></script>
</head>
<body>
    <div id="root">
        <h2>hello,{{name}}</h2>
        <button v-on:click="showInfo1">点我提示信息1</button>
        <button @click="showInfo2($event,66)">点我提示信息2</button>
    </div>

    <script>
        Vue.config.productionTip = false 
        new Vue({
            el:'#root', 
            data:{
                name:'JOJO'
            },
            methods:{
                showInfo1(event){
                    console.log(event)
                },
                showInfo2(evnet,num){
                    console.log(event,num)
                }
            }
        })
    </script>
</body>
</html>

事件修饰符：
1prevent:阻止默认事件
2stop阻止事件冒泡
3once事件只触发一次
4capture使用事件的捕获模式
5self:只有event.target是当操作的元素才是触发事件
6passive:事件的而默认行为立即实行，无需等待事件回调执行完毕

6键盘事件

vue按键别名
回车enter,
删除delete
退出esc
空格space
换行tab
上up
下down
left.right

注意：

系统修饰键（用法特殊）：ctrl、alt、shift、meta

配合keyup使用：按下修饰键的同时，再按下其他键，随后释放其他键，事件才被触发
配合keydown使用：正常触发事件
可以使用keyCode去指定具体的按键，比如：@keydown.13=“showInfo”，但不推荐这样使用

Vue.config.keyCodes.自定义键名 = 键码，可以自定义按键别名

8姓名案例
9计算属性

拿已经写完的属性加工成计算生成全新属性
data写属性
computed计算新属性

<!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="./js/vue.js"></script>
</head>
<body>
    <div id="root">
        姓：<input type="text" v-model="firstname"><br>
        名: <input type="text" v-model="lastname">
        <br>全名：<span>{{fullname}}</span>
    </div>
    <script>
        const vm = new Vue({
            el:'#root',
            data:{
                firstname:'张',
                lastname:'san'
            },
            computed:{
                fullname:{ //只要调用fullname就会执行
                    get(){
                        console.log('调用了getter')
                        return this.firstname+'-_-'+this.lastname
                    }
                }
            }
                
        })
    </script>
</body>
</html>