These tools generally don't work for dynamic languages, only for static languages, like Java. Also, as I said, its far from perfect, however even the Intellij I

These tools generally don't work for dynamic languages, only for static languages, like Java. Also, as I said, its far from perfect, however even the Intellij IDE that I use has some features like this and makes some helpful suggestions. For example, if you needlessly reassign a variable (reassign it twice before it could be read by anything) it catches this, it catches some of the mistakes that developers tend to make when they've been hacking away for hours and are not paying close attention and thus helps to clean up the code.