Get all runtime global variables set by the app

getAllGlobals.js

/**
 * RuntimeGlobalsChecker
 *
 * You can use this utility to quickly check what variables have been added (or
 * leaked) to the global window object at runtime (by JavaScript code).
 * By running this code, the globals checker itself is attached as a singleton
 * to the window object as "__runtimeGlobalsChecker__".
 * You can check the runtime globals programmatically at any time by invoking
 * "window.__runtimeGlobalsChecker__.getRuntimeGlobals()".
 *
 */
window.__runtimeGlobalsChecker__ = (function createGlobalsChecker() {
  // Globals on the window object set by default by the browser.
  // We collect them to then filter them out of from the list of globals (since
  // we don't care about them).
  // They're populated by "collectBrowserGlobals()" and will contain globals such
  // as "location" and "localStorage".
  let browserGlobals = [];
 
  // Known globals on the window object that we can safely ignored.
  // This list should be populated manually after trial and errors.
  const ignoredGlobals = ["__runtimeGlobalsChecker__"];
 
  /**
   * Collect the global variables added to the window object by the browser by
   * creating a temporary iframe and checking what global variables the browser
   * adds on it.
   * @returns {string[]} - List of globals added added by the browser
   */
  function collectBrowserGlobals() {
    const iframe = window.document.createElement("iframe");
    iframe.src = "about:blank";
    window.document.body.appendChild(iframe);
    browserGlobals = Object.keys(iframe.contentWindow);
    window.document.body.removeChild(iframe);
    return browserGlobals;
  }
 
  /**
   * Return the list of globals added at runtime (by JavaScript).
   * @returns {string[]} - List of globals added at runtime (by JavaScript)
   */
  function getRuntimeGlobals() {
    // If we haven't collected the browser globals yet, do it now.
    if (browserGlobals.length === 0) {
      collectBrowserGlobals();
    }
    // Grab all the globals filtering out variables we don't care about (noise).
    const runtimeGlobals = Object.keys(window).filter((key) => {
      const isFromBrowser = browserGlobals.includes(key);
      const isIgnored = ignoredGlobals.includes(key);
      return !isFromBrowser && !isIgnored;
    });
    return runtimeGlobals;
  }
 
  return {
    getRuntimeGlobals,
  };
})();

How to implement

• Copy and paste the getAllGlobals.js into the devtools console
• Load your runtime globals into a variable so we don't have to keep querying the globals

let rg = __runtimeGlobalsChecker__.getRuntimeGlobals();

• Sort* and print the current runtime globals

rg.sort().forEach((i) => {console.log(i)});

* Note about sorting. I had initially had all of this in the script, however, I ran into a few sites that for whatever reason complete Bork when you try sort the stored globals. I'm sure there's a bug there to dig into but it was annoying enough that I could just have it in there. If you run into an issue where you get errors on the sort, you will have to avoid sorting and just print to console how it is and you'll have to do a little manual mucking about.