Chaos Proxy: JavaScript Shenanigans

Source: Dev.to

Chaos Proxy Overview

JavaScript Proxy objects can intercept and redefine fundamental operations. This example demonstrates a simple proxy that randomly returns either the original function’s result or an alternative result, based on a configurable error probability.

Implementation

const chaosProxy = (source, odds, alternative) => new Proxy(source, {
  apply(target, context, args) {
    // Return the alternative result with probability `odds`
    return Math.random() - odds >= 0
      ? alternative.apply(context, args)
      : target.apply(context, args);
  }
});

• source – the original function to proxy.
• odds – probability of returning the alternative result (as a fraction of 1).
• alternative – a fallback function to execute when the error occurs.

Example Usage

const circleArea = radius => Math.PI * radius ** 2;
const circleAreaClose = radius => 3.14 * radius ** 2;

// 50 % chance of using the less‑accurate approximation
const roughArea = chaosProxy(circleArea, 0.5, circleAreaClose);

console.log(roughArea(2)); // → 12.566370614359172 (accurate)
console.log(roughArea(2)); // → 12.56 (approximate)

Running roughArea repeatedly will produce a mix of accurate and approximate results, illustrating how the proxy can inject nondeterministic behavior.

Extensions and Ideas

• Multiple alternatives – assign different weights/probabilities to several fallback functions.
• Async handling – manipulate Promise values or introduce random delays in asynchronous responses.
• Argument mutation – modify the arguments object before forwarding to see how mutations affect your application.
• Deterministic sequences – replace the random choice with a predefined sequence of responses for reproducible testing.

Experimenting with these variations can deepen your understanding of JavaScript’s proxy mechanics and help you build more resilient code.