Issue #3419730 by catch, Spokje: [jQuery 4] TypeError: $.isArray is not a...

     */

    verifyConstraints(constraints, selector) {

      let result;

      if ($.isArray(constraints)) {

      if (Array.isArray(constraints)) {

        // This constraint is an array (OR or XOR).

        const hasXor = $.inArray('xor', constraints) === -1;

        const len = constraints.length;