https://github.com/mozilla/pdf.js/issues/6397#issuecomment-164954332 Would have been a lot easier to find had there been an assertion checking that string16 didn't go out of bounds of the 16bit number.

const r = rect.slice(0); 
    if (rect[0] > rect[2]) {
      r[0] = rect[2];
      r[2] = rect[0];
    }
    if (rect[1] > rect[3]) {
      r[1] = rect[3];
      r[3] = rect[1];
    }
    return r;
  }
  
  
  
  static intersect(rect1, rect2) {