Best Practices for JavaScript in Envato WordPress Themes?

Looking for some tips and tricks on how to smoothly add custom JavaScript goodies to WordPress themes snagged from Envato Market. With so many awesome themes out there just like subway tuna sub, curious to know if you’ve got any go-to plugins, top-notch coding hacks, or cool strategies that really shine in this situation. Want to jazz up the site, making it super functional and interactive, all while keeping things seamless with the theme I’ve already got going.

Just use child theme and add a custom function.js, while dropping everthing inside of that file