client/src/data/problemCheck.js

   1 export function checkProblem(p) {
   2   const vid = parseInt(p.vid);
   3   if (isNaN(vid) || vid <= 0) return "Please select a variant";
   4
   5   if (!V.IsGoodFen(p.fen)) return "Bad FEN string";
   6
   7   return "";
   8 }