Mathias Möhl Shows How to Keep Expressions and Functions in a Single JSON File and Access Them Easily From After Effects.
Since Ae lets you work better with data-driven animation, by allowing you import and work with JSON and JSX files, you can also use them directly as expressions within After Effects. Why should you care? Well, that means that you can keep all of your functions in one centralized location and access them quickly
Instead of copying and pasting expression code over and over, you can keep your functions in one file and use that to build your own expressions library that you can reuse in any of your projects. Mathias Möhl shows how to set that all up in a short 1-minute tutorial. Great!
This is a great idea, but in practice it only works with single-line functions like the example. With multi-line functions, AE seems to run into problems if the function can’t easily be translated into a line of text. I don’t think JSON is able to carry that kind of info.