[sgslo]

I've used it to extend the functionality of a library without having to monkeypatch or subclass a bunch of classes. See here: https://github.com/StephenGrider/AdvancedNodeComplete/blob/m...

The CustomPage class 'extends' through the use of a proxy a Page and Browser class, while adding its own methods on top. The proxy mediates access to the Custompage instance, and the Page and Browser. When calling a method on CustomPage, it first looks to see if the method exists on the CustomPage instance, then the Browser instance, then the Page.

I had originally wanted to subclass Page, which is implemented by the Puppeteer library, but the Browser class had a dozen direct references to the Page class. I would have had to sublcass the Browser as well and override all those methods to instead reference my CustomPage. The proxy seemed like an appropriate solution.