Great news folks! An extension for Visual Studio Code (VSC) is available that supports JXA scripts.
I've just started testing it, but so far, so good.
If you haven't used VSC, I highly recommend it. It is free and has great features. Among them is code completion, which is far superior to Script Editor.
I hope some of you with join with me in learning and testing the JXA extension for VSC. Please post your questions, issues, and/or suggestions here.