1. Object flattening in JavaScript, this is favourite question here. 2. Given two array arr1 and arr2. Find common union of the elements and then next subsequent question find out the common elements. 3. Given array of objects and each object contains source and destination, find the path from source to destination. Then they told that unless untill it is not mentioned, from destination you can not go to source. Then they started asking nodejs questions, event loop and setTimeout call apply bind etc.. this interview went for 1.5hr. But one thing is for sure, once you pass this interview, 95% you are selected. Remaining all interview with person was about your communication and how you have been till here in carrier related questions etc...