javascript-standart-library/proxy.html at main · azamiset/javascript-standart-library · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Proxy</title>
</head>
<body>
<script>

    const target = {
        middleName: "Kurniawan"
    };

    const handler = {
        get: function (target, property) {
            console.info(`Access property : ${property}`);
            return target[property];
        },
        set: function (target, property, value) {
            console.info(`Change property ${property} : ${value}`)
            if(value == null){
                // throw new Error("Tidak boleh null");
                target[property] = "";
            }else{
                target[property] = value;
            }
        }
    };

    const proxy = new Proxy(target, handler);
    proxy.firstName = "Eko";
    proxy.lastName = null;

    console.info(proxy.firstName);
    console.info(proxy.middleName);
    console.info(proxy.lastName);
    console.info(target);

</script>
</body>
</html>