My manager reaction? He was pissed that I had done it against a mock API instead of the inexisting …

… My manager reaction? He was pissed that I had done it against a mock API instead of the inexisting real one, told me to wait until the end-points were ready and integrate them and wouldn't give me any other work otherwise despite of my best arguments. What happened is during the next 3 months I was basically writing and rewriting the app, becoming very proficient in React. Then the manager started to hear heat from above, and he started to complain about my coworker in a very similar situation of this article, so I started to look for a new job. That backend coworker left few days after me and never came back (I was probably the only non-hostile one, even friendly, to him at work by that point).