Prototype ¬ Detail

author: layer51 [+], Submitted: 05.26.03 8a

//------------------------------------------------------
// ::: DATE OBJECT ENHANCEMENT
// Created by: Luke Bayes
// Please send any comments, corrections or modifications
// to : luke@lukebayes.com
// Otherwise you are free to use this code for any reason
// in any application.

// When using addTime or removeTime the UNIT argument
// will be used to identify which unit of time to
// add to the current date object -
// it should be one of the following string values:
//
// ms == milliseconds
// ss == seconds
// mi == minutes
// hh == hours
// dd == days
// wk == weeks
// mm == months
// yyyy == years
//
// VAL will be the numeric measurement to add
//------------------------------------------------------
// EXAMPLE USAGE:
// var myDay = new Date();
// myDay.addTime("dd", 2);
// trace("myDay : " + myDay);
// myDay.addTime("yyyy", 2);
// trace("myDay : " + myDay);
// myDay.removeTime("mm", 3);
// trace("myDay : " + myDay);

//------------------------------------------------------
// ::: PUBLIC DATE METHODS BELOW -
//------------------------------------------------------
// Return the difference between the current date object
// and the one passed in as dateRef. Return value is in the
// unit specified. (any supported above)...
// will Round results by default, pass boolean true in doNotRound
// argument to return complex numbers.
Date.prototype.getTimeDiff = function(unit, dateRef, doNotRound)
{
	if(!(dateRef instanceof Date))
		return

	if(!this.customInited)
		this.customInit();

	var oms = dateRef.getTime();
	var mms = this.getTime();
	var diff = (mms - oms < 0) ? oms - mms : mms - oms;

	return (doNotRound) ? diff / this.unitValues[unit] : Math.round(diff / this.unitValues[unit]);
}

//------------------------------------------------------
// Will add the amount of time specified to the current date
// object in the units passed in. See above for supported
// units.
Date.prototype.addTime = function(unit, amt)
{
	if(isNaN(amt))
		return
	else
		var amt = Number(amt);

	if(!this.customInited)
		this.customInit();

	if(unit == "mm") {
		this.setMonth( this.getMonth() + amt );
	} else if(unit == "yyyy") {
		this.setFullYear( this.getFullYear() + amt );
	} else {
		var actual = this.unitValues[unit] * amt;
		this.setTime( this.getTime() + actual );
	}
}

//------------------------------------------------------
// Will remove time from the current date object in the
// units specified. See above for supported units.
Date.prototype.removeTime = function(unit, amt)
{
	this.addTime(unit, -amt);
}

//------------------------------------------------------
// ::: PRIVATE HELPER METHODS BELOW -
//------------------------------------------------------

Date.prototype.getUnitsInMilliseconds = function()
{
	var obj = new Object();
	obj.ms = 1;
	obj.ss = 1000;
	obj.mi = obj.ss * 60;
	obj.hh = obj.mi * 60;
	obj.dd = obj.hh * 24;
	obj.wk = obj.dd * 7;
	obj.mm = obj.dd * 30;
	obj.yyyy = obj.dd * 365;
	return obj;
}

//------------------------------------------------------

Date.prototype.customInit = function()
{
	this.unitValues = this.getUnitsInMilliseconds();
	this.customInited = true;
}

//------------------------------------------------------

trace(">> Date Loaded");

usage

trace("date start : " + myDate);
var myDate = new Date();
myDate.addTime("mm", 3);
trace("date finish : " + myDate);