Sprout Social Software Engineer - Front End interview questions

I found an internship job posting on Glassdoor and applied through their website. About a few days later, I received an email prompting me to complete a coding challenge. Please know that even know I was requesting to be a front-end intern, the questions are general software engineering questions with code being written in Java, Python, or C/C++. After completing this, a few weeks later I set up a call with one of the recruiters to have a brief chat about my background and resume. Here, I let my recruiter know that I was interested in front-end development. After another follow-up call a few months later, I was asked to fly out to Chicago for an onsite! At the onsite interview, I had 4 back-to-back interviews concerning different aspects of front-end development. Everyone there is extremely nice and it's almost like having an intellectual discussion with peers. I had interviews over Javascript, UI design, my coding background and design approach. I only had to whiteboard my initial design for a website. During the interview process, I was given lunch and a tour of their awesome office. It was very easygoing and a good look into how working there would be like.