Robert C. Martin (aka Unkle Bob) wrote the book Clean Code; this is an attempt to translate those principles to JavaScript code, but do note:
One more thing: knowing these won’t immediately make you a better software developer, and working with them for many years doesn’t mean you won’t make mistakes. Every piece of code starts as a first draft, like wet clay getting shaped into its final form. Finally, we chisel away the imperfections when we review it with our peers. Don’t beat yourself up for first drafts that need improvement. Beat up the code instead!