A few months back, I applied for a backend engineering position at a company. I did a few programming challenges and had a few interviews, and got an idea of the projects they were working on (Go and Ruby on Rails were mentioned, both with which I have some experience.) After not receiving a response after the last interview, I took another offer.
A couple weeks ago I was called back, asking if I was interested in a DevOps position (I've been wanting to start focusing on that type of work, so I would have passed on it if it was for the original position I applied) so I agreed to a couple more interviews. The interviewers didn't really have a good idea of what I'd be working on, but I asked infrastructure/devops focused questions and based on that information it seemed like a good fit. They gave me an offer, and I accepted.
Now that I've been here a week, I've been put on an application development team, doing work exclusively on a Node.js project (which was not mentioned in any of the interviews.) I'm not opposed to learning new technologies, but I have no experience with Node and would rather work somewhere that I can build experience with something else.
With that said, am I justified in leaving this job after a week? I feel misled (whether intentionally or not.) I'm not worried about being out of work until I can find something else.