手写 vue3 Proxy reactive 双向绑定原理

Proxy 代理对象

手写 vue3 Proxy reactive 双向绑定原理_第1张图片


Vue3 Proxy 双向绑定原理

一定要触发set,才能够修改到界面的数据。
因为Object.defineproperty 如果对象是数组,不会触发set,所以在vue2.0中,数组并不是响应式的。
因为new Proxy 可以对数组进行代理,修改数组中数据的时候,也会触发set,一旦触发set,就可以在set中修改界面的数据,做到响应式效果

<!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>
    <input type="text" id="ipt">
    <p id="op"></p>
    <script>
        let obj = { txtVal: '输入框的默认值' }

        let newObj = new Proxy(obj, {
            get(target, property) {
                console.log("target", target);
                console.log("property", property);
                return target[property]
            }
        })

        ipt.value = newObj.txtVal 
        op.innerHTML = newObj.txtVal
        addEventListener('input', (e) => {
            console.log(e.target.value);
            op.innerHTML = e.target.value
        })
    </script>
</body>
</html>

手动输入内容 p标签的内容也会改变
手写 vue3 Proxy reactive 双向绑定原理_第2张图片


封装 myReactive


<!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>
    <input type="text" id="ipt">
    <p id="op"></p>
    <script>
        let obj = { txtVal: '输入框的默认值' }
        
        function myReactive(obj) {
            return new Proxy(obj, {
                get(target, property) {
                    return target[property]
                },
                set(target, property, newValue) {
                    ipt.value = newValue; // 输入框的值
                    op.innerHTML = newValue // p标签展示的值
                }
            })
        }
        let newO = myReactive(obj);
        addEventListener('input', (e) => {
            newO.txtval = e.target.value
        })
    </script>
</body>
</html>

手写 vue3 Proxy reactive 双向绑定原理_第3张图片


手写 vue3 reactive

<!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>
    <input type="text" id="ipt">
    <p id="op"></p>
    <script>
        let obj = { txtVal: '输入框的默认值' } 
        
        function myReactive() {
            return new Proxy(obj, {
                get(target, property) {
                    return target[property]
                }
            })
        }
        myReactive(obj)
        ipt.value = obj.txtVal
        op.innerHTML = obj.txtVal
    </script>
</body>

</html>

手写 vue3 Proxy reactive 双向绑定原理_第4张图片

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