User Script that tracks postMessage event listeners and makes it easy to track/debug them

postMessageTracker.js

// ==UserScript==
// @name        PostMessage Tracker
// @namespace   Violentmonkey Scripts
// @match       *://*/*
// @version     1.0
// @author      Ounissi zakaria (https://twitter.com/zakaria_ounissi)
// @description Each time an event listener is added for `message` it adds a menu command to tha message handler.
// @grant GM.registerMenuCommand
// @run-at document-start
// ==/UserScript==


// Create a variable to store the original addEventListener method
var originalAddEventListener = unsafeWindow.addEventListener;

function onClick(listener) {
    return (function () {
        console.log(listener)
        const handler = {
            get(target, prop, receiver) {
                console.trace("Tracing postMessage listener", prop)
                debugger;
                return Reflect.get(...arguments);
            },
        };
        e = new Proxy({ data: { milk: true }, origin: "https://z98.pro", lastEventId: "989898", source: "1", ports: ["1"] }, handler);
        console.log(listener(e))
    })
}


// Override the addEventListener method
unsafeWindow.addEventListener = function (type, listener, options) {
    // Call the original addEventListener method
    originalAddEventListener.apply(this, arguments);

    if (arguments[0].toLowerCase() === "message") {
        GM.registerMenuCommand(listener.toString(), onClick(listener))
    }
};