In computer programming, a code smell is any characteristic in the source code of a program which possibly indicates a deeper problem.

Determining what is a code smell and what is not a code smell is subjective, and varies by language, developer, and development methodology.

The two main know open source tools used for JavaScript code analysis are JSLint and JSHint, the second being a fork of the first one. There are however many different tools that try to achieve the same goal and you might find something more suited to your own needs.