Differentiating PathText shape

// select areaText or pathText textFrame
var Ps = app.selection[0].textPath.pathPoints;
var polygon = true;
for (var i = 0; i < Ps.length; i++) {
    var test = Ps[i].anchor[0] == Ps[i].rightDirection[0] && 
               Ps[i].rightDirection[0] == Ps[i].leftDirection[0] && 
               Ps[i].anchor[1] == Ps[i].rightDirection[1] && 
               Ps[i].rightDirection[1] == Ps[i].leftDirection[1];
    if (!test) {
        polygon = test;
        break;
    }
}
if (polygon) alert("polygon");
if (!polygon) alert("non-polygon");