Hi Annette,
I use PHP Storm for WordPress development, and it is an amazing tool. It is a fully featured IDE, as you noted in your question, but a bit overpowered for JavaScript editing. Web Storm is lighter weight due to the lack of PHP features and I’ve found it faster to work with for JavaScript, especially when doing additional tasks like compiling Sass, ES6, etc. PHP Storm will work just fine for JavaScript but I’d encourage you to try Web Storm – I’d be interested to see if you like the experience as I have.
Cheers,
Andrew