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Quick Start

Overview​

Nexos extends JavaScript’s built-in Proxy by adding an event-driven layer that gives you more visibility and control over how proxies behave. Instead of writing custom handlers manually for each proxy, you can listen to lifecycle events and handler traps like get, set, defineProperty, and more — globally or per proxy.

This quick start guide demonstrates how to create proxies with Nexos and how to react to proxy events. We’ll start with a standard JavaScript proxy example, then explore how Nexos simplifies and enhances this process with event-driven functionality.

1. Standard JavaScript Proxy​

The traditional way to intercept property access on an object:

const target = { message: "Hello, world!" };
const handler = {
  get(target, property) {
    console.log(`Property '${property}' accessed.`);
    return target[property];
  },
};

const proxy = new Proxy(target, handler);
console.log(proxy.message); // Logs: Property 'message' accessed.

In this example, you must manually define the handler. Nexos removes that burden and gives you global access to proxy operations through events.

2. Nexos Proxy with Event Listener​

Nexos lets you create a proxy and attach listeners to trap events like get, set, or even creation itself:

import { Nexo } from "nexos";

const nexo = new Nexo();
const proxy = nexo.create({ message: "Hello, world!" });

nexo.on("proxy.get", (event) => {
  console.log(`Property '${event.data.property}' accessed.`);
});

console.log(proxy.message); // Logs: Property 'message' accessed.

Here, proxy.get is emitted whenever a property is accessed, and we react to it through the listener.

3. Listening to Proxy Creation​

Track whenever a new proxy is created — useful for logging, debugging, or assigning custom metadata:

nexo.on("proxy", (event) => {
  console.log("A new proxy has been created:", event.target);
});

const proxy = nexo.create({ key: "value" });
// Logs: A new proxy has been created: { key: "value" }

The event includes a unique proxy and its metadata.

4. Creating Virtual Proxies (No Target)​

You can also create proxies without a real object behind them. Nexos handles operations using a sandbox:

const virtualProxy = nexo.create();
virtualProxy.hello = "virtual";

console.log(virtualProxy.hello); // Prints: virtual

This is helpful for dynamic or placeholder objects where the structure is unknown at runtime.

5. Reacting to Property Changes​

Let’s now intercept property assignments using the "proxy.set" event:

const proxy = nexo.create({});

nexo.on("proxy.set", (event) => {
  console.log(`Setting property '${event.data.property}' to`, event.data.value);
});

proxy.name = "Nexos"; // Logs: Setting property 'name' to Nexos

This works globally for all proxies managed by the same Nexo instance.

🚀 Next Steps​

Nexos makes proxies more powerful, observable, and testable — perfect for building reactive systems, debugging, and dynamic API layers.