twitter.datehelper.js

// Adapted from code provided by 37Signals on their Signal vs. Noise blog.
// Added support for Twitter date parsing.

// Call DateHelper.time_ago_in_words_with_parsing(twitter_date_as_string) to use.

var DateHelper = {
  date_parse_from_twitter: function(str){
  	parts = str.match(/^([a-z]{3}) ([a-z]{3}) (\d{2}) (\d{2}):(\d{2}):(\d{2}) \+(\d{4}) (\d{4})$/i);
  	if(!parts) return false;
  	var date_str = parts[1] + ", " + parts[3] + " " + parts[2] + " " + parts[8] + " " + parts[4] + ":" + parts[5] + ":" + parts[6] + " GMT";
  	var date = new Date(date_str);
  
  	return date;
  },

  time_ago_in_words_with_parsing: function(from) {
	
    var date = this.date_parse_from_twitter(from); 
	if(!date) return "";
    return this.time_ago_in_words(date);
  },
  
  time_ago_in_words: function(from) {
    return this.distance_of_time_in_words(new Date, from);
  },

  distance_of_time_in_words: function(to, from) {

    var distance_in_seconds = ((to - from) / 1000);
    var distance_in_minutes = Math.floor(distance_in_seconds / 60.0);

    if (distance_in_minutes == 0) { return 'less than a minute ago'; };
    if (distance_in_minutes == 1) { return 'a minute ago'; };
    if (distance_in_minutes < 45) { return distance_in_minutes + ' minutes ago'; };
    if (distance_in_minutes < 90) { return 'about 1 hour ago'; };
    if (distance_in_minutes < 1440) { return 'about ' + Math.floor(distance_in_minutes / 60) + ' hours ago'; };
    if (distance_in_minutes < 2880) { return '1 day ago'; };
    if (distance_in_minutes < 43200) { return Math.floor(distance_in_minutes / 1440) + ' days ago'; };
    if (distance_in_minutes < 86400) { return 'about 1 month ago'; };
    if (distance_in_minutes < 525960) { return Math.floor(distance_in_minutes / 43200) + ' months ago'; };
    if (distance_in_minutes < 1051199) { return 'about 1 year ago'; };
    return 'over ' + Math.floor(distance_in_minutes / 525960) + ' years ago';
  }
};