Libraries like bluebird will give you pretty stack traces that track the sequence of then calls, almost as if it was a single sequential execution. This helps w

Libraries like bluebird will give you pretty stack traces that track the sequence of then calls, almost as if it was a single sequential execution. This helps with debugging. Alternatively you can use the yield-spawn method of getting rid of then() altogether. Then you get code that looks sequential as well, and the browser gives you nice stack traces. This doesn't help with modifying values during debugging as you mentioned, but it does solve the problem of seeing the "caller" stack frames.