- Electron version: v1.3.4 and HEAD.

Node's [`process.exit`](https://nodejs.org/api/process.html#process_process_exit_code) takes an **optional** code argument, which defaults to `0`.

Electron's [`app.exit`](http://electron.atom.io/docs/api/app/#appexitexitcode) takes a **required** code argument.

So the current [`process.exit = app.exit`](https://github.com/electron/electron/blob/b5dec9990eb34a711c57a4f639b2c4c8de866d5f/lib/browser/init.js#L101) breaks electron's `process`-api compatibility with node.

Which causes unhappiness.  For example, when asking `argparse` to print help and exit.  This `(new require('argparse').ArgumentParser()).parseArgs(['--help'])` complains `.: error: Error processing argument at index 0, conversion failure from undefined`.

 `process.exit = app.exit` could be changed to something like `process.exit = function AppExitWithOptionalCode (exitCode) { return app.exit(exitCode || 0); }`.  In node v5.4.1 at least, `process.exit(undefined)` behaves the same as `process.exit()`.  Or perhaps a more precise `app.exit.apply(app, arguments.length ? arguments : [0])`.

atom/browser/browser.h
observers_.AddObserver(obs);
  }
  void RemoveObserver(BrowserObserver* obs) {
    observers_.RemoveObserver(obs);
  }
  bool is_shutting_down() const { return is_shutdown_; }
  bool is_quiting() const { return is_quiting_; }
  bool is_ready() const { return is_ready_; }
 protected:
  
  std::string GetExecutableFileVersion() const;