This is similar to the Revealing Module Pattern in Learning JavaScript Design Patterns: https://addyosmani.com/resources/essentialjsdesignpatterns/b...

I think it's perfectly readable, and it requires no more language hacks that obfuscate the JavaScript underlying `class` syntax sugar.

I often use a functional style as the OP's above, instead of classes, but I wonder about performance hit. Calling it often (like many "instances") and creating new functions every time seem less efficient that inheriting methods via prototype.

If I were to create 300 instances of something with actual func^H^H^H^H methods attached, rather than 3 instances, I would probably look into creating a prototype and coping with the perils of “this” usage, but otherwise, I’m not going to lose much sleep about it.

Yes, especially if the result is only used in a small number of nearby places, which is usually the case.

My IDE can easily infer the properties of such objects, as well as display the JSDoc for such properties.

This is why macros and a homoiconic language are such a good thing: you can add syntax sugar to have something which is both straightforwardly implemented and readable.