// BAD get(target, prop) { return target[prop]; // Ignores proxy inheritance } // GOOD get(target, prop, receiver) { return Reflect.get(target, prop, receiver); // Maintains correct this } Sometimes you need a proxy made with reflect that can be revoked. Use Proxy.revocable .
Start refactoring your proxies today—replace manual logic with Reflect and watch your code become more reliable, elegant, and performant. Further Reading: MDN Web Docs – Proxy & Reflect, TC39 Proposal Details, "Metaprogramming in JavaScript" by Keith Kirk. Have a specific use case? Drop a comment below. proxy made with reflect 4 top
function createLazyProxy(initializer) { let instance = null; return new Proxy({}, { get(target, prop, receiver) { if (!instance) { console.log("Initializing expensive resource..."); instance = initializer(); } const value = Reflect.get(instance, prop, instance); return typeof value === 'function' ? value.bind(instance) : value; } }); } const heavyDB = createLazyProxy(() => { // Simulate expensive connection return { query: (sql) => Result for: ${sql} , status: "connected" }; }); // BAD get(target, prop) { return target[prop]; //
: It uses Reflect to capture the exact value, including getters that might compute results dynamically. 3. Validation Proxy (Top Security) A common requirement is to validate data before allowing mutations. This pattern powers libraries like Vuex and MobX. Further Reading: MDN Web Docs – Proxy &
const target = { name: "AdvancedJS", version: "ES2024" }; const handler = { get: function(obj, prop) { if (prop === 'name') { return `[Secured] ${obj[prop]}`; } return obj[prop]; } }; const proxy = new Proxy(target, handler); This works, but it's brittle. What happens when the property is a getter? What about inheritance? Enter Reflect . The Reflect API is a built-in object that provides methods for interceptable JavaScript operations. Every method on Reflect has a corresponding trap on Proxy . When you build a proxy made with reflect , you stop guessing how the default behavior should work and simply invoke Reflect to handle it correctly.
function createTransparentProxy(target) { return new Proxy(target, { get(target, prop, receiver) { return Reflect.get(target, prop, receiver); }, set(target, prop, value, receiver) { return Reflect.set(target, prop, value, receiver); }, has(target, prop) { return Reflect.has(target, prop); }, deleteProperty(target, prop) { return Reflect.deleteProperty(target, prop); }, apply(target, thisArg, argumentsList) { return Reflect.apply(target, thisArg, argumentsList); }, construct(target, argumentsList, newTarget) { return Reflect.construct(target, argumentsList, newTarget); } }); } Using Reflect ensures that if the target object has native getters or inherits from a prototype, the proxy respects those behaviors without additional code. One of the "top" use cases is logging without breaking the application logic.
const validatedPerson = createValidationProxy(person, ageValidator); validatedPerson.age = 30; // Works // validatedPerson.age = -5; // Throws TypeError