How to use @AndroidFindBy and @iOSFindBy in appium +Javascript

I am trying to create one test case to test both iOS and Android platforms. How to use @AndroidFindBy and @iOSFindBy tags in Javascript?
The elements in my native apps (iOS and Android) many times don’t have common attributes. So I would like to have a Page Object approch, where I can define elements for both platforms and call from test.
Any help is appreciated.