I have written a function for deleting object preiodically.

function add(variable, expireSecond){

    this.list[variable] = {expireSecond: expireSecond, addTime: (new Date().getTime()) / 1000};

}



function deleteExpiredObject(){

    var currentTime = (new Date().getTime()) / 1000;

    for (var key in this.list) {

        var item = this.list[key];

        if (item.expireSecond + item.addTime < currentTime){

            delete this.list[key];

        }

    }

}

When I use it, I tried to do the following:

add(xxx[1], 300);

But when I called deleteExpiredObject(), it seems that the memory is not free after the object is expired. Is it due to non-zero reference of the object in xxx[1]? How to solve? Is there any library I can use?

Thanks!