I've worked on several large Rails apps and seen at least a dozen javascript systems. In this post I'll describe a few techniques that I've seen that consistently make javascript easier to test and maintain. To those of you who write javascript more than I do, these might be old news, but it's taken me 4 years to learn them!

TDD is an iterative development process where each iteration starts by writing a test which forms a part of the specification we are implementing. The short iterations allow for more instant feedback on the code we are writing, and bad design decisions are easier to catch. By writing the tests prior to any production code, good unit test coverage comes with the territory, but that is merely a welcome side-effect.