JavaScript 데이터 undefined 체크하기

var dData = caller.gridView01.getData();

dData.forEach(function(n){
    if (typeof n.liveWeight === "undefined" || n.liveWeight == null || n.liveWeight == "") {
        frmYn = "N";
    }
    if (typeof n.weightIndex === "undefined" || n.weightIndex == null || n.weightIndex == "") {
        frmYn = "N";
    } 
    if (typeof n.fatIndex === "undefined" || n.fatIndex == null || n.fatIndex == "") {
        frmYn = "N";
    }  
});