Is increment an atomic operation in JavaScript?

in Javascript always a function runs to completions that means if a function is running than it will run completely , only after that the other function will be called so , there is no chance of interleaving between statements( but in case of java it is different ) ,if you are confused with asynchronous execution than always remember async means later not parallel , So, coming to your problem, the answer is ,No you will not face any problem, it will be total atomic operation.

Javascript is single threaded, So you need to worry about deallocks or dirty read problems. Why doesn't JavaScript support multithreading?