Currently, each babel plugin in the babel ecosystem requires that you configure it individually. This is fine for things like language features but can be a frustrating overhead for libraries that allow for compile-time code transformation as an optimization. babel-plugin-macros defines a standard interface for libraries that want to use compile-time code transformation without requiring the user to add a babel plugin to their build system (other than babel-plugin-macros, which is ideally already in place). There is cpu usage/time overhead; the client needs to run the code to generate these classes every time the page loads. ...