File yui3/src/date/js/date-math.js
/**
* Date Math submodule.
*
* @module datatype-date
* @submodule datatype-date-math
* @for Date
*/
var LANG = Y.Lang;
Y.mix(Y.namespace("Date"), {
/**
* Checks whether a native JavaScript Date contains a valid value.
* @for Date
* @method isValidDate
* @param oDate {Date} Date in the month for which the number of days is desired.
* @return {Boolean} True if the date argument contains a valid value.
*/
isValidDate : function (oDate) {
if(LANG.isDate(oDate) && (isFinite(oDate)) && (oDate != "Invalid Date") && !isNaN(oDate) && (oDate != null)) {
return true;
}
else {
Y.log("Could not validate data as type Date", "warn", "date");
return false;
}
},
/**
* Checks whether two dates correspond to the same date and time.
* @for Date
* @method areEqual
* @param aDate {Date} The first date to compare.
* @param bDate {Date} The second date to compare.
* @return {Boolean} True if the two dates correspond to the same
* date and time.
*/
areEqual : function (aDate, bDate) {
return (this.isValidDate(aDate) && this.isValidDate(bDate) && (aDate.getTime() == bDate.getTime()));
},
/**
* Checks whether the first date comes later than the second.
* @for Date
* @method isGreater
* @param aDate {Date} The first date to compare.
* @param bDate {Date} The second date to compare.
* @return {Boolean} True if the first date is later than the second.
*/
isGreater : function (aDate, bDate) {
return (this.isValidDate(aDate) && this.isValidDate(bDate) && (aDate.getTime() > bDate.getTime()));
},
/**
* Checks whether the first date comes later than or is the same as
* the second.
* @for Date
* @method isGreaterOrEqual
* @param aDate {Date} The first date to compare.
* @param bDate {Date} The second date to compare.
* @return {Boolean} True if the first date is later than or
* the same as the second.
*/
isGreaterOrEqual : function (aDate, bDate) {
return (this.isValidDate(aDate) && this.isValidDate(bDate) && (aDate.getTime() >= bDate.getTime()));
},
/**
* Checks whether the date is between two other given dates.
* @for Date
* @method isInRange
* @param aDate {Date} The date to check
* @param bDate {Date} Lower bound of the range.
* @param cDate {Date} Higher bound of the range.
* @return {Boolean} True if the date is between the two other given dates.
*/
isInRange : function (aDate, bDate, cDate) {
return (this.isGreaterOrEqual(aDate, bDate) && this.isGreaterOrEqual(cDate, aDate));
},
/**
* Adds a specified number of days to the given date.
* @for Date
* @method addDays
* @param oDate {Date} The date to add days to.
* @param numDays {Number} The number of days to add (can be negative)
* @return {Date} A new Date with the specified number of days
* added to the original date.
*/
addDays : function (oDate, numDays) {
return new Date(oDate.getTime() + 86400000*numDays);
},
/**
* Adds a specified number of months to the given date.
* @for Date
* @method addMonths
* @param oDate {Date} The date to add months to.
* @param numMonths {Number} The number of months to add (can be negative)
* @return {Date} A new Date with the specified number of months
* added to the original date.
*/
addMonths : function (oDate, numMonths) {
var newYear = oDate.getFullYear();
var newMonth = oDate.getMonth() + numMonths;
newYear = Math.floor(newYear + newMonth / 12);
newMonth = (newMonth % 12 + 12) % 12;
var newDate = new Date (oDate.getTime());
newDate.setFullYear(newYear);
newDate.setMonth(newMonth);
return newDate;
},
/**
* Adds a specified number of years to the given date.
* @for Date
* @method addYears
* @param oDate {Date} The date to add years to.
* @param numYears {Number} The number of years to add (can be negative)
* @return {Date} A new Date with the specified number of years
* added to the original date.
*/
addYears : function (oDate, numYears) {
var newYear = oDate.getFullYear() + numYears;
var newDate = new Date(oDate.getTime());
newDate.setFullYear(newYear);
return newDate;
},
/**
* Lists all dates in a given month.
* @for Date
* @method listOfDatesInMonth
* @param oDate {Date} The date corresponding to the month for
* which a list of dates is required.
* @return {Array} An `Array` of `Date`s from a given month.
*/
listOfDatesInMonth : function (oDate) {
if (!this.isValidDate(oDate)) {
return [];
}
var daysInMonth = this.daysInMonth(oDate),
year = oDate.getFullYear(),
month = oDate.getMonth(),
output = [];
for (var day = 1; day <= daysInMonth; day++) {
output.push(new Date(year, month, day, 12, 0, 0));
}
return output;
},
/**
* Takes a native JavaScript Date and returns the number of days
* in the month that the given date belongs to.
* @for Date
* @method daysInMonth
* @param oDate {Date} Date in the month for which the number
* of days is desired.
* @return {Number} A number (either 28, 29, 30 or 31) of days
* in the given month.
*/
daysInMonth : function (oDate) {
if (!this.isValidDate(oDate)) {
return 0;
}
var mon = oDate.getMonth();
var lengths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
if (mon != 1) {
return lengths[mon];
}
else {
var year = oDate.getFullYear();
if (year%400 === 0) {
return 29;
}
else if (year%100 === 0) {
return 28;
}
else if (year%4 === 0) {
return 29;
}
else {
return 28;
}
}
}
});
Y.namespace("DataType");
Y.DataType.Date = Y.Date;