components/src/ZenCommonUtils.mjs

var gZenOperatingSystemCommonUtils = {
  kZenOSToSmallName: {
    WINNT: 'windows',
    Darwin: 'macos',
    Linux: 'linux',
  },

  get currentOperatingSystem() {
    let os = Services.appinfo.OS;
    return this.kZenOSToSmallName[os];
  },
};

class ZenMultiWindowFeature {
  constructor() {}

  static get browsers() {
    return Services.wm.getEnumerator('navigator:browser');
  }

  static get currentBrowser() {
    return Services.wm.getMostRecentWindow('navigator:browser');
  }

  isActiveWindow() {
    return ZenMultiWindowFeature.currentBrowser === window;
  }

  async foreachWindowAsActive(callback) {
    if (!this.isActiveWindow()) {
      return;
    }
    for (const browser of ZenMultiWindowFeature.browsers) {
      try {
        await callback(browser);
      } catch (e) {
        console.error(e);
      }
    }
  }
}

class ZenDOMOperatedFeature {
  constructor() {
    var initBound = this.init.bind(this);
    document.addEventListener('DOMContentLoaded', initBound, { once: true });
  }
}

class ZenPreloadedFeature {
  constructor() {
    var initBound = this.init.bind(this);
    document.addEventListener('MozBeforeInitialXULLayout', initBound, { once: true });
  }
}