Prettyprint formating for JS Date objects, without library.

js_prettyprint_date.js

Date.prototype.customFormat = function(formatString){
  var YYYY,YY,MMMM,MMM,MM,M,DDDD,DDD,DD,D,hhh,hh,h,mm,m,ss,s,ampm,AMPM,dMod,th;
  var dateObject = this;
  YY = ((YYYY=dateObject.getFullYear())+"").slice(-2);
  MM = (M=dateObject.getMonth()+1)<10?('0'+M):M;
  MMM = (MMMM=["January","February","March","April","May","June","July","August","September","October","November","December"][M-1]).substring(0,3);
  DD = (D=dateObject.getDate())<10?('0'+D):D;
  DDD = (DDDD=["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"][dateObject.getDay()]).substring(0,3);
  th=(D>=10&&D<=20)?'th':((dMod=D%10)==1)?'st':(dMod==2)?'nd':(dMod==3)?'rd':'th';
  formatString = formatString.replace("#YYYY#",YYYY).replace("#YY#",YY).replace("#MMMM#",MMMM).replace("#MMM#",MMM).replace("#MM#",MM).replace("#M#",M).replace("#DD\
DD#",DDDD).replace("#DDD#",DDD).replace("#DD#",DD).replace("#D#",D).replace("#th#",th);
  h=(hhh=dateObject.getHours());
  if (h==0) h=24;
  if (h>12) h-=12;
  hh = h<10?('0'+h):h;
  AMPM=(ampm=hhh<12?'am':'pm').toUpperCase();
  mm=(m=dateObject.getMinutes())<10?('0'+m):m;
  ss=(s=dateObject.getSeconds())<10?('0'+s):s;
  return formatString.replace("#hhh#",hhh).replace("#hh#",hh).replace("#h#",h).replace("#mm#",mm).replace("#m#",m).replace("#ss#",ss).replace("#s#",s).replace("#amp\
m#",ampm).replace("#AMPM#",AMPM);
};

var t = _.template(
  "<% var prettytime = (new Date(timestamp)).customFormat( '#MMMM# #DD#, #YYYY# #hh#:#mm# #AMPM#' ).toUpperCase(); %>"+
  "<div class=\"byline\"><%= prettytime %></div>"
);