Class Helper

browser_patches/firefox/juggler/Helper.js:7–171

const uuidGen = Cc["@mozilla.org/uuid-generator;1"].getService(Ci.nsIUUIDGenerator);

export class Helper {
  decorateAsEventEmitter(objectToDecorate) {
    const { EventEmitter } = ChromeUtils.importESModule('resource://gre/modules/EventEmitter.sys.mjs');
    const emitter = new EventEmitter();
    objectToDecorate.on = emitter.on.bind(emitter);
    objectToDecorate.addEventListener = emitter.on.bind(emitter);
    objectToDecorate.off = emitter.off.bind(emitter);
    objectToDecorate.removeEventListener = emitter.off.bind(emitter);
    objectToDecorate.once = emitter.once.bind(emitter);
    objectToDecorate.emit = emitter.emit.bind(emitter);
  }

  collectAllBrowsingContexts(rootBrowsingContext, allBrowsingContexts = []) {
    allBrowsingContexts.push(rootBrowsingContext);
    for (const child of rootBrowsingContext.children)
      this.collectAllBrowsingContexts(child, allBrowsingContexts);
    return allBrowsingContexts;
  }

  awaitTopic(topic) {
    return new Promise(resolve => {
      const listener = () => {
        Services.obs.removeObserver(listener, topic);
        resolve();
      }
      Services.obs.addObserver(listener, topic);
    });
  }

  toProtocolNavigationId(loadIdentifier) {
    return `nav-${loadIdentifier}`;
  }

  addObserver(handler, topic) {
    Services.obs.addObserver(handler, topic);
    return () => Services.obs.removeObserver(handler, topic);
  }

  addMessageListener(receiver, eventName, handler) {
    receiver.addMessageListener(eventName, handler);
    return () => receiver.removeMessageListener(eventName, handler);
  }

  addEventListener(receiver, eventName, handler, options) {
    receiver.addEventListener(eventName, handler, options);
    return () => {
      try {
        receiver.removeEventListener(eventName, handler, options);
      } catch (e) {
        // This could fail when window has navigated cross-process
        // and we remove the listener from WindowProxy.
        // Nothing we can do here - so ignore the error.
      }
    };
  }

  awaitEvent(receiver, eventName) {
    return new Promise(resolve => {