Angular filter to convert a time in milliseconds to relative human readable time

angular_relativeDate.js

(function(){
"use strict":
angular.module('ng-relativeDate',[])
.filter('ngrelativeDate',function(){
        /**
         * [humanreadableDate converts the timestamp into human readable time ]
         * @param {Int} timestamp - time as number of milliseconds since 1970/01/01:
         * @return {string} relative time corresponding to timestamp  
         */

        var humanReadableDate = function (timestamp){
        var now = new Date();
        var midnightToday = new Date(now.getFullYear(), now.getMonth(), now.getDate(), 0, 0, 0).getTime();
        var firstOfTheYear = new Date(now.getFullYear(), 0, 1, 0, 0, 0).getTime();
        var nowTime = (new Date().getTime());
        var timeDiff = (nowTime - timestamp)/1000;
        var minsAgo = Math.floor(timeDiff/60);
        var hoursAgo = Math.floor(timeDiff/3600);
        var text;
       
        if (timeDiff > 0 && timeDiff < 22 *3600) {
            if (timeDiff < 60) {
                text = 'few seconds ago';
            }
            else if (timeDiff < 92) {
                text = 'a minute ago';
            }
            else if (timeDiff < 3300) {
                text = minsAgo + " mins ago";
            }
            else if (timeDiff < 5400) {
                text = 'an hour ago';
            }
            else if (timeDiff < 22 * 3600) {
                text = 'about ' + hoursAgo + ' hour ago';
            }
        } else {
            var year =  parseInt(new Date(timestamp).getFullYear()) < 
                parseInt(new Date().getFullYear())          ?
                new Date(timestamp).getFullYear()+" ,":""; 
            text = year+convertTimeToString(timestamp, midnightToday, firstOfTheYear);
        }
        return text;
    }

    return humanReadableDate;
    });
}).call(this);

This is cool.. But getting an error..
where is the convertTimeToString() method implementation..?? are you missing it or me...??

I was missing it , will fix