JSHint is helpful, especially (I think) for people who don't write a ton of JS. Unit tests are obviously important. I've been using Istanbul lately to check my

JSHint is helpful, especially (I think) for people who don't write a ton of JS. Unit tests are obviously important. I've been using Istanbul lately to check my test coverage, and that's made a big difference. It's awesome to be able to see, quickly, that "Oh. I'm not even testing half of this function." Sticking to some kind of style guide also helps. Idiomatic.js is a good starting point. Also, doing some basic checking on your own is often a good idea. Look at your arguments, make sure they're what you expect, and if now, throw an error. That'll make it a bit easier to see where your problems are, since you won't have to dig around stack traces as much.