CoffeeScript date utilities

date.coffee

Number::pad = (digits, signed) ->
  s = Math.abs(@).toString()
  s = "0" + s while s.length < digits
  (if @ < 0 then "-" else (if signed then "+" else "")) + s

Date.months = [ "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" ]
Date.weekdays = [ "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" ]

Date.formats =
  "a": -> Date.weekdays[@getDay()].substring(0, 3)
  "A": -> Date.weekdays[@getDay()]
  "b": -> Date.months[@getMonth()].substring(0, 3)
  "B": -> Date.months[@getMonth()]
  "c": -> @toLocaleString()
  "d": -> @getDate().toString()
  "F": -> "#{@getFullYear()}-#{@getMonth() + 1}-#{@getDate()}"
  "H": -> @getHours().pad(2)
  "I": -> "#{(@getHours() % 12) || 12}"
  "j": -> @getDayOfYear()
  "L": -> @getMilliseconds().pad(3)
  "m": -> (@getMonth() + 1).pad(2)
  "M": -> @getMinutes().pad(2)
  "N": -> @getMilliseconds().pad(3)
  "p": -> if @getHours() < 12 then "AM" else "PM"
  "P": -> if @getHours() < 12 then "am" else "pm"
  "S": -> @getSeconds().pad(2)
  "s": -> Math.floor(@getTime() / 1000)
  "U": -> @getWeekOfYear()
  "w": -> @getDay()
  "W": -> @getWeekOfYear(1)
  "y": -> @getFullYear() % 100
  "Y": -> @getFullYear()
  "x": -> @toLocaleDateString()
  "X": -> @toLocaleTimeString()
  "z": -> Math.floor((z = -@getTimezoneOffset()) / 60).pad(2, true) + (Math.abs(z) % 60).pad(2)
  "Z": -> /\(([^\)]*)\)$/.exec(@toString())[1]

Date::format = (fmt) ->
  parts = (fmt || "%c").split "%%"
  for own char, callback of Date.formats
    r = new RegExp("%#{char}", "g")
    parts = (part.replace(r, => callback.apply(this)) for part in parts)
  parts.join "%"
  
Date::getDayOfYear = -> Math.ceil((@getTime() - new Date(@getFullYear(), 0, 1).getTime()) / 24 / 60 / 60 / 1000)

Date::getWeekOfYear = (start = 0) ->
  Math.floor((@getDayOfYear() - (start + 7 - new Date(@getFullYear(), 0, 1).getDay()) % 7) / 7) + 1

date.coffee.js

// Automatically compiled to JavaScript

var __hasProp = Object.prototype.hasOwnProperty;

Number.prototype.pad = function(digits, signed) {
  var s;
  s = Math.abs(this).toString();
  while (s.length < digits) {
    s = "0" + s;
  }
  return (this < 0 ? "-" : (signed ? "+" : "")) + s;
};

Date.months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];

Date.weekdays = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];

Date.formats = {
  "a": function() {
    return Date.weekdays[this.getDay()].substring(0, 3);
  },
  "A": function() {
    return Date.weekdays[this.getDay()];
  },
  "b": function() {
    return Date.months[this.getMonth()].substring(0, 3);
  },
  "B": function() {
    return Date.months[this.getMonth()];
  },
  "c": function() {
    return this.toLocaleString();
  },
  "d": function() {
    return this.getDate().toString();
  },
  "F": function() {
    return "" + (this.getFullYear()) + "-" + (this.getMonth() + 1) + "-" + (this.getDate());
  },
  "H": function() {
    return this.getHours().pad(2);
  },
  "I": function() {
    return "" + ((this.getHours() % 12) || 12);
  },
  "j": function() {
    return this.getDayOfYear();
  },
  "L": function() {
    return this.getMilliseconds().pad(3);
  },
  "m": function() {
    return (this.getMonth() + 1).pad(2);
  },
  "M": function() {
    return this.getMinutes().pad(2);
  },
  "N": function() {
    return this.getMilliseconds().pad(3);
  },
  "p": function() {
    if (this.getHours() < 12) {
      return "AM";
    } else {
      return "PM";
    }
  },
  "P": function() {
    if (this.getHours() < 12) {
      return "am";
    } else {
      return "pm";
    }
  },
  "S": function() {
    return this.getSeconds().pad(2);
  },
  "s": function() {
    return Math.floor(this.getTime() / 1000);
  },
  "U": function() {
    return this.getWeekOfYear();
  },
  "w": function() {
    return this.getDay();
  },
  "W": function() {
    return this.getWeekOfYear(1);
  },
  "y": function() {
    return this.getFullYear() % 100;
  },
  "Y": function() {
    return this.getFullYear();
  },
  "x": function() {
    return this.toLocaleDateString();
  },
  "X": function() {
    return this.toLocaleTimeString();
  },
  "z": function() {
    var z;
    return Math.floor((z = -this.getTimezoneOffset()) / 60).pad(2, true) + (Math.abs(z) % 60).pad(2);
  },
  "Z": function() {
    return /\(([^\)]*)\)$/.exec(this.toString())[1];
  }
};

Date.prototype.format = function(fmt) {
  var callback, char, part, parts, r, _ref;
  parts = (fmt || "%c").split("%%");
  _ref = Date.formats;
  for (char in _ref) {
    if (!__hasProp.call(_ref, char)) continue;
    callback = _ref[char];
    r = new RegExp("%" + char, "g");
    parts = (function() {
      var _i, _len, _results,
        _this = this;
      _results = [];
      for (_i = 0, _len = parts.length; _i < _len; _i++) {
        part = parts[_i];
        _results.push(part.replace(r, function() {
          return callback.apply(_this);
        }));
      }
      return _results;
    }).call(this);
  }
  return parts.join("%");
};

Date.prototype.getDayOfYear = function() {
  return Math.ceil((this.getTime() - new Date(this.getFullYear(), 0, 1).getTime()) / 24 / 60 / 60 / 1000);
};

Date.prototype.getWeekOfYear = function(start) {
  if (start == null) start = 0;
  return Math.floor((this.getDayOfYear() - (start + 7 - new Date(this.getFullYear(), 0, 1).getDay()) % 7) / 7) + 1;
};