Reflect 4 Proxy May 2026

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
public class LoggingHandler implements InvocationHandler 
private final Object target; // real object
public LoggingHandler(Object target) 
    this.target = target;
@Override
public Object invoke(Object proxy, Method method, Object[] args) 
        throws Throwable 
    // Log before execution
    System.out.println("[LOG] Calling: " + method.getName());
    if (args != null) 
        for (int i = 0; i < args.length; i++) 
            System.out.println("[LOG] Arg " + i + ": " + args[i]);
// Invoke the real method via reflection
    Object result = method.invoke(target, args);
// Log after execution
    System.out.println("[LOG] Returned: " + result);
return result;

If the user is specifically looking for the NPM package reflect-proxy, version 4 introduced middleware support for altering the reflection. reflect 4 proxy

npm install -g reflect-proxy@4

Configuration file (reflect.config.json):

  "version": 4,
  "port": 8080,
  "mode": "echo",
  "reflection": 
    "addHeaders": true,
    "stripAuth": false,
    "maxBodySize": "10mb"

Run the server:

reflect-proxy --config reflect.config.json

Testing it:

curl -X POST http://localhost:8080/api/test \
  -H "Content-Type: application/json" \
  -H "X-Debug-Token: mySecret" \
  -d '"hello":"world"'

Expected Output (Reflected):

  "originalMethod": "POST",
  "originalPath": "/api/test",
  "originalHeaders": 
    "content-type": "application/json",
    "x-debug-token": "mySecret",
    "host": "localhost:8080"
  ,
  "originalBody": 
    "hello": "world"
  ,
  "timestamp": "2025-01-27T12:00:00Z"

const user =  name: "Alice", age: 25 ;
const handler = 
get(target, prop, receiver) 
console.log(GET $prop);
return Reflect.get(target, prop, receiver);
,
set(target, prop, value, receiver) ,
has(target, prop) 
console.log(HAS $prop);
return Reflect.has(target, prop);
,
deleteProperty(target, prop) 
console.log(DELETE $prop);
return Reflect.deleteProperty(target, prop);
;
const pUser = new Proxy(user, handler);
pUser.age = 30;      // SET age=30
console.log(pUser.name); // GET name → Alice
console.log('age' in pUser); // HAS age → true
delete pUser.name;   // DELETE name