First round is usually an algorithm based coding exam, 1-2 questions are asked in a definite time interval and you need to clear this round to proceed.
The second round is a technical interview, where you are judged on your code writing and domain knowledge skills.
After this round, a third round might or might not happen depending upon your job title or employer's requirement.
Interview questions [1]
Question 1
Q) What is the significance of promises and callbacks in JS?