js判断一个对象数组里是否存在某个元素

对象数组

 var trackObj1={
                    "trackId":31,
                    "direcLine":"line31"
                 };
var currentTrack=[];

         currentTrack.push(trackObj1);

var trackObj2={

                    "trackId":30,

                    "direcLine":"line30"

                 };

  currentTrack.push(trackObj2);

判断currentTrack这个数组中是否存在trackId=31的对象

/*按照属性值，查找对象*/
function findElem(arrayToSearch,attr,val){
    for (var i=0;i         if(arrayToSearch[i][attr]==val){
            return i;
        }
    }
    return -1;
}

 var index=findElem(currentTrack,"trackId","31");

参考网址：https://debugmode.net/2013/02/19/how-to-find-index-of-an-item-in-javascript-object-array/