I'm not so sure about this. It is certainly js standard, but I notice not using it in coffeescript as much. Especially in standalone examples like this one I'm not convinced. Camelcase has proven advantages in readability (if you're interested I'll try to recover the research paper on this). I'm not too sure it is agreed which style is better in the coffeescript community either:

https://github.com/jashkenas/coffee-script/issues/425

Personally I think the standard should be that naming is consistent per exercise. I think that reflects real world programs the best as well.