For such a technical role you will be asked about regular expressions, a bit of JavaScript and basic algorithms like binary search (with insertion point). If you are seasoned developer, the interview will be easy and they will give you enough time to think over the answers. There's a lot of turnover in this company, so any advice about people would be outdated. This is probably an indication that it is not a good company for most people to work in but your mileage may vary.