1) System test - Build a very small application in Reactjs (including babel/webpack setup) 2) Javascript - Spread/Rest, let vs var, Arrow Functions, ES^ Promises vs callbacks 3) CSS3 - Block Model, Media Queries, Inline Block vs Float, Position absolute vs fixed vs relative 4) jQuery Promise vs Generators vs Async/Await 5) How does Node.js Middleware work? 6) When does browser paint event trigger? How do you debug browser performance issues? 7) And some algorithm problems in Javascript (which also require very good understanding of prototype inheritance, this keyword and map/reduce/filter)