Resource for Refactoring tips geared towards JavaScript

I'd like to start a discussion on the best resources for refactoring tips, with an eye towards Front-End JavaScript refactoring.

A friend whose opinion I respect suggests this book, though it uses examples in Java. I understand that the principles of OO refactoring should translate to another language.

Let's talk about refacto开发者_运维问答ring in general and JS refactoring specifically.

Check out Martin's Clean Code for some inspiration. The examples are in Java but the ideas should translate to JavaScript as well.

In order to refactor properly, you'll need to test your code well as having proper tests in place is a prerequisite for it. Try finding testing tools that give you code coverage as this will be extremely valuable.

In case your code hasn't been tested yet you can think testing as a method of learning. You write tests to prove or disprove your assumptions about it. Once you are done and covered it adequately you should be able to refactor the code using various patterns provided.

As Ira mentioned having a tool to detect clones may be valuable. That's definitely one way to look at it.

I think that often having proper perspective is half the solution. If you can state your design in clear terms, you'll end up with better results. Try not to over-engineer it too much by applying every possible pattern you find. :)

Not specifically a refactoring tool, but a tool to detect the number one smell in code: our CloneDR automatically finds duplicated code (copy/paste/edit) and shows you the precise locations and a reasonable abstraction of each clone. You have to resolve the clones by hand, but knowing where they are and having been provided that first cut at an abstraction, is a big help.

EDIT: This is directly a resource for refactoring of Java and JavaScript code. CloneDR works for both of them, using langauge-precise parsing to give precise analysis of clones.

You can see sample clone detection results on Google's Javascript Closure package.