如何通过PassByReference传输webdriver-io的浏览器对象

I'm using webdriver-io v3.x in combination with Mocha. To be able to test identical components on different sites I'd like to outsource the test into an extra function. To achieve this I have to transfer the browser object via some kind of PassByReference to this extra function. How can I do this?I'm using webdriver-io v3.x in combination with