Right now we use codemirror's JavaScript mode on the website but there's a JSX mode now so we should start using that instead.

newPos.ch += dir;
              if (newPos.ch < 0) {
                if (newPos.line > doc.first) newPos = clipPos(doc, Pos(newPos.line - 1));
                else newPos = null;
              } else if (newPos.ch > line.text.length) {
                if (newPos.line < doc.first + doc.size - 1) newPos = Pos(newPos.line + 1, 0);
                else newPos = null;
              }
              if (!newPos) {
                if (flipped) {
                  
                  
                  if (!mayClear) return skipAtomic(doc, pos, bias, true);
                  
                  doc.cantEdit = true;
                  return Pos(doc.first, 0);
                }
                flipped = true; newPos = pos; dir = -dir;
              }
            }
            curPos = newPos;
            continue search;
          }
        }
      }
      return curPos;
    }
  }
  
  function scrollCursorIntoView(cm) {