I've been using the .prototype method for the stuff I've been working on, primarily because that's 'just how it's done' for .NET AJAX client-side behaviors/extenders.

Here's what you need to know about object-oriented programming with classes, methods, objects, and interfaces, with examples in Java, Python, and TypeScript. Object-oriented programming (OOP) is ...

Private class fields are finally coming to JavaScript with no less than three separate TC39 proposals that define the new capabilities.