This topic explains how to work with date values in JavaScript and gives examples of date operations. It contains the following sections:

Objects and Functions for Working With Date Values

Getting Tomorrow’s and Yesterday’s Dates

Calculating the Year and Month Duration

### Basics

When writing scripts we often deal with dates. There are certain date value formats and TestComplete routines that help handle dates.

Since the TestComplete scripting engine only supports OLE-compatible data types, the date-time values are implemented as floating-point variant values in a special format. The integer part of this value represents the number of days that have passed since December 30, 1899. The number after the decimal separator represents the fraction of a 24-hour period that has elapsed. However, you do not have to understand what these floating-point values represent. TestComplete provides several routines that help you convert these values to their string representation (see below).

Below are some examples of date-time values and their meaning:

Value | Meaning |
---|---|

0.25 | December 30, 1899. 6:00 AM |

36345.5 | July 4, 1999. 12:00 PM |

39094.65625 | January 12, 2007. 3:45 PM |

When you are only working with date values the fractional part can be omitted.

### Objects and Functions for Working With Date Values

TestComplete has the `aqDateTime`

object that contains methods that can be useful when operating with dates.

Method | Description |
---|---|

AddDays | Adds or subtracts the specified number of days to (from) the given date. |

AddMonths | Adds or subtracts the specified number of months to (from) the given date. |

AddTime | Adds or subtracts the specified number of days, hours, minutes and seconds to (from) the given date. |

Compare | Compares two specified date/time values. |

GetDay | Returns the ordinal number of a day in a month. |

GetDayOfWeek | Returns the day of the week for the specified date. |

GetDayOfYear | Returns the ordinal number of a day in a year. |

GetMonth | Returns the month number of the specified date. |

GetYear | Returns the year number of the specified date. |

IsLeapYear | Indicates whether the specified year is a leap year. |

Now | Returns the current date and time. |

SetDateElements | Returns the Date variable having the specified year, month and day. |

SetDateTimeElements | Returns the Date variable having the specified date and time portions. |

SetSystemDateTime | Assigns the specified date and time as the system date and time. |

Today | Returns the current date. |

One more object, `aqConvert`

, provides methods to convert strings between date values and their string equivalents:

Method | Description |
---|---|

DateTimeToFormatStr | Converts the given date value to a string using the specified format. |

DateTimeToStr | Converts the given date value to a string. |

StrToDate | Converts the specified string to a date value. |

StrToDateTime | Converts the specified string to a date/time value. |

The `aqDateTime`

and `aqConvert`

objects are available for all supported scripting languages, so that you can use them to operate with date values regardless of the chosen language.

### Getting Current Date

There are two routines that return current date: `Today`

and `Now`

. The difference between them is that the value returned by the `Now`

routine includes both the date and time parts, whereas the `Date`

routine returns only the date part. The script below demonstrates how to use them.

JavaScript

**function** GetDate()

{

**let** TodayValue, NowValue, StringTodayValue, StringNowValue, VariantTodayValue, VariantNowValue

*// Obtain the current date*

TodayValue = aqDateTime.Today();

*// Obtain the current date and time*

NowValue = aqDateTime.Now();

*// Convert the returned date/time values to the string values*

StringTodayValue = aqConvert.DateTimeToStr(TodayValue);

StringNowValue = aqConvert.DateTimeToStr(NowValue);

*// Post the converted values to the log*

Log.Message("The date obtained from the Today routine is " + StringTodayValue);

Log.Message("The date obtained from the Now routine is " + StringNowValue);

*// Convert the floating-point values to the string values*

VariantTodayValue = aqConvert.FloatToStr(TodayValue);

VariantNowValue = aqConvert.FloatToStr(NowValue);

*// Post the converted values to the log*

Log.Message("The variant representation of TodayValue is " + VariantTodayValue);

Log.Message("The variant representation of NowValue is " + VariantNowValue)

}

### Getting Tomorrow’s and Yesterday’s Dates

The sample below demonstrates how the `aqDateTime`

object can be used to calculate
tomorrow's date. The current date is obtained via the `aqDateTime.Today`

method. Then the current date value is incremented via the `aqDateTime.AddDays`

method.
The `DateTimeToStr`

method of the `aqConvert`

object is used to convert the date value into a string that is posted to the TestComplete log.

JavaScript

**function** TomorrowDate()

{

*// Obtain the current date*

**let** CurrentDate = aqDateTime.Today();

*// Convert the date/time value to a string and post it to the log*

Today = aqConvert.DateTimeToStr(CurrentDate);

Log.Message("Today is " + Today);

*// Calculate the tomorrow’s date, convert the returned date to a string and post this string to the log*

Tomorrow = aqDateTime.AddDays(CurrentDate, 1);

ConvertedTomorrowDate = aqConvert.DateTimeToStr(Tomorrow);

Log.Message("Tomorrow will be " + ConvertedTomorrowDate);

**return** Tomorrow;

}

Similarly, you can calculate any date that differs from the current day by a certain amount of days: yesterday, next or previous week and so forth. For example, to get yesterday’s date, you have to pass -1 as the second parameter of the `aqDateTime.AddDays`

method.

JavaScript

**function** YesterdayDate()

{

*// Obtain the current date*

**let** CurrentDate = aqDateTime.Today();

*// Convert the date/time value to a string and post it to the log*

Today = aqConvert.DateTimeToStr(CurrentDate);

Log.Message("Today is " + Today);

*// Calculate the yesterday’s date, convert the returned date to a string and post this string to the log*

YesterdayDate = aqDateTime.AddDays(CurrentDate, -1);

ConvertedYesterdayDate = aqConvert.DateTimeToStr(YesterdayDate);

Log.Message("Yesterday was " + ConvertedYesterdayDate);

}

### Calculating the Year and Month Duration

Generally there are 365 days in a calendar year. However the length of an astronomical year is about 365.242375 days, so in the course of time the fractional part would result in an extra day and the calendar year would lag from the astronomical. To avoid this the leap year that is 366 days long was invented.

The Gregorian calendar is the current standard calendar in most of the world and it adds a 29th day to February in all years evenly divisible by 4, except for centennial years (those ending in -00), which only receive the extra day if they are evenly divisible by 400. The `aqDateTime`

object has a special method `IsLeapYear`

that accepts the year number and returns **true** if the specified year is a leap year. We can use this method to get the exact number of days in the desired year:

JavaScript

**function** DaysInYear(YearNo)

{

**return** 365 + aqDateTime.IsLeapYear(YearNo);

}

In the sample above, the Boolean value was converted into an integer since JavaScript allows implicit type conversion.

Using the `IsLeapYear`

method we can get the number of days in the month. For all months, except February, the duration of a month is fixed and is either 30 or 31 days. The duration of February is 28 or 29 days depending on whether the current year is a leap year or not. The routine that gets the month duration would be the following:

JavaScript

**function** DaysInMonth(MonthNo, YearNo)

{

**switch** (MonthNo)

{

**case** 1: **case** 3: **case** 5: **case** 7: **case** 8: **case** 10: **case** 12: **return** 31;

**case** 2: **if** (aqDateTime.IsLeapYear(YearNo)) **return** 29; **return** 28;

**case** 4: **case** 6: **case** 9: **case** 11: **return** 30;

}

}

### Comparing Dates

To compare date/time values, use the `aqDateTime.Compare`

method rather than comparison operators (like ==, >, <, != and others) provided by the scripting engine:

JavaScript

r = aqDateTime.Compare(DateTime1, DateTime2);**if** (r > 0)

*// DateTime1 > DateTime2***else**

**if** (r < 0)

*// DateTime1 < DateTime2*

**else**

*// equal(DateTime1, DateTime2)*

This note does not concern the `Date`

objects provided by the JavaScript engine. To compare `Date`

objects, use the features provided by the engine.

### Encoding and Decoding Date Values

Because the date values are represented as variants, special routines are required that convert the variant value to a calendar date format and back. These operations are performed by the SetDateElements, GetYear, GetMonth and GetDay methods of the `aqDateTime`

object. These methods take into account whether the current year is a leap year and the number of days in a month so that the resulting value is guaranteed to be valid. The `SetDateElements`

accepts the parts of date and returns the variant date value.

JavaScript

**function** EncodeDateDemo()

{

*// Create a Date variable having the specified year, month and day* values

**let** myDate = aqDateTime.SetDateElements(2005, 12, 25);

*// Convert the value of the myDate variable to a string using the specified format and post this string to the log*

EncodedDate = aqConvert.DateTimeToFormatStr(myDate,"%B/%#d/%Y");

Log.Message("The encoded date is "+ EncodedDate);

*// Convert the value of the myDate variable to a variant value and post it to the log*

VariantDate = aqConvert.IntToStr(myDate);

Log.Message("The variant representation of it is "+ VariantDate);

}

The `GetYear`

, `GetMonth`

and `GetDay`

methods accept the variant date-time value and return the respective date parts of that value. Here is an example of how to use these routines:

JavaScript

**function** DecodeDateDemo()

{

*// Obtain the current date*

**let** CurrentDate = aqDateTime.Today();

*// Return the parts of the current date value and then post them to the log*

**let** Year = aqDateTime.GetYear(CurrentDate);

**let** Month = aqDateTime.GetMonth(CurrentDate);

**let** Day = aqDateTime.GetDay(CurrentDate);

Log.Message(Day + " day(s) have passed since the beginning of the " + Month + " month of " + Year + " year.");

}

### Modifying Date Values

Despite the fact that date-time values are represented as floating-point numbers, you cannot explicitly use ordinary arithmetic operators to change dates or times. However, the `aqDateTime`

scripting object provides a number of methods that are especially designed to modify date-time values. These methods are: `AddMonths`

, `AddDays`

and `AddTime`

. The `AddTime`

method allows to modify date and time portions at once.

As you may notice from the Getting Tomorrow’s and Yesterday’s Dates section, these methods are used both for incrementing and decrementing of date-time values. When the positive number is passed as Month, Days or another parameter, then the resulting value is increased. If the parameter is negative, then the resulting value is decreased.

These methods take into account the number of days in the month, whether the year is a leap and other aspects of time calculations, that is why the resulting value is guaranteed to be valid.

The code below demonstrates how to use these methods:

JavaScript

**function** ModifyDates()

{

**let** Date, AlteredDate;

Date = aqDateTime.SetDateElements(2007, 1, 25);

*// Increase the date by 7 days*

*// Note the month changing *

AlteredDate = aqDateTime.AddDays(Date, 7);

Log.Message("Initial date: " + aqConvert.DateTimeToStr(Date));

Log.Message("Altered date 1: " + aqConvert.DateTimeToStr(AlteredDate));

*// Increase the date by one month *

*// Note that 28 days were added since the month is February *

AlteredDate = aqDateTime.AddMonths(AlteredDate, 1);

Log.Message("Altered date 2: " + aqConvert.DateTimeToStr(AlteredDate));

*// Decrease the date by 1 day*

AlteredDate = aqDateTime.AddTime(AlteredDate, -1, 0, 0, 0);

Log.Message("Altered date 3: " + aqConvert.DateTimeToStr(AlteredDate));

}

### Dealing With Week Days

Besides recognizing the date, month and year, you may need to know which day of the week a certain date falls. The `aqDateTime.GetDayOfWeek`

method performs this task. It accepts the variant date and returns the number of the week day that corresponds to it. The returned number ranges between 1 and 7, where 1 corresponds to Sunday, 2 - to Monday, and so forth. The sample code below obtains the current date, calculates the day of the week and posts the name of the day to the log.

JavaScript

**function** DayOfWeekDemo()

{

**let** WeekDay, DayName;

WeekDay = aqDateTime.GetDayOfWeek(aqDateTime.Today());

**switch** (WeekDay)

{

**case** 1: DayName = "Sunday"; **break**;

**case** 2: DayName = "Monday"; **break**;

**case** 3: DayName = "Tuesday"; **break**;

**case** 4: DayName = "Wednesday"; **break**;

**case** 5: DayName = "Thursday"; **break**;

**case** 6: DayName = "Friday"; **break**;

**case** 7: DayName = "Saturday"; **break**;

}

Log.Message("Today is " + DayName);

}

**Note: **The `GetDayOfWeek`

method uses the United States system of week notation where the week is considered to start on Sunday and end on Saturday. However, the ISO 8601 *“Data elements and interchange formats - Information interchange - Representation of dates and times”* standard recommends another system of a week notation. In this system the week starts on Monday and ends on Sunday. To convert the US Week day number to ISO 8601 you can use the following routine:

JavaScript

**function** ISODayOfWeek(InputDate)

{

**let** ReturnDate = aqDateTime.GetDayOfWeek(InputDate) - 1;

**if** (equal(ReturnDate, 0)) ReturnDate = 7;

**return** ReturnDate;

}

The result of this function is also an integer number, but 1 corresponds to Monday, 2 to Tuesday and so on.

In addition to the day of the week, we can find out the week boundaries that the specified date belongs, that is, calculate the dates that the week starts and ends. This could be done using the following two routines. Here the number of a week day is subtracted from the specified date to get the beginning of a week, and to get the end of the week, six days are added to the calculated date.

JavaScript

**function** StartOfWeek (InputDate)

{

*// If the input parameter is omitted then current date is taken*

**if** (strictEqual(InputDate, undefined)) InputDate = aqDateTime.Today();

*// Using US week day number*

**return** aqDateTime.AddDays(InputDate, - aqDateTime.GetDayOfWeek(InputDate) + 1);

*// Using ISO week day number*

*// return aqDateTime.AddDays(InputDate, - ISODayOfWeek(InputDate) + 1);*

}**function** EndOfWeek (InputDate)

{

*// If the input parameter is omitted then current date is taken*

**if** (strictEqual(InputDate, undefined)) InputDate = aqDateTime.Today();

*// Using US week day number*

**return** aqDateTime.AddDays(InputDate, - aqDateTime.GetDayOfWeek(InputDate) + 7);

*// Using ISO week day number*

*// return aqDateTime.AddDays(InputDate, - ISODayOfWeek(InputDate) + 7);*

}

**Note: **Since the routines use the `aqDateTime.GetDayOfWeek`

method, which returns the US week day number, the dates returned by the routines are Sunday and Saturday, correspondingly. To apply the ISO 8601 week day notation, you should use the last code line, where the `aqDateTime.GetDayOfWeek`

call is replaced with a call to `ISODayOfWeek`

function. (The code of the `ISODayOfWeek`

function is provided in the note above.) In this case the first routine would return the date that falls on Monday and the second one, the date that falls on Sunday.

Another frequent operation when dealing with dates is calculating the number of weeks that have passed since the beginning of the year. First we should clarify what week should be considered as the first week of a year. According to the ISO 8601 standard, the first week of a year is a week with the majority (four or more) of days in the starting year. In our case it is better to use another equivalent definition of the first week: the week with the date, January, 4th.

Here is the routine that calculates the week number in compliance with this rule. It accepts the date that belongs to the desired week, determines the end of this week and the end of the week that includes January 4, and that calculates the week number as the difference between those two values divided by 7.

JavaScript

**function** WeekNumber(InputDate)

{

**let** YearNo = aqDateTime.GetYear(InputDate);

**let** EndOfFirstWeek = EndOfWeek(aqDateTime.SetDateElements(YearNo,1,4));

**let** EndOfCurrentWeek = EndOfWeek(InputDate);

**return** 1 + (aqDateTime.GetDayOfYear(EndOfCurrentWeek) - aqDateTime.GetDayOfYear(EndOfFirstWeek)) / 7;

}

Sometimes it is useful to know what day of the week the desired month starts or ends. The routines below return the week day number that correspond to the beginning and end of the month. They only have one input parameter that specifies the date which belongs to the desired month. If the parameter is missing then the routines return the results for the current month. The routines are similar to calculating the beginning and end of a week, but instead of the week day number, the day of the month number is used.

JavaScript

**function** StartOfMonthDay (InputDate)

{

*// If the input parameter is omitted then current date is taken*

**if** (isUndefined(InputDate)) InputDate = aqDateTime.Today();

**let** StartDate = aqDateTime.AddDays(InputDate, - aqDateTime.GetDay(InputDate)+1);

*// Using US week day number*

**return** aqDateTime.GetDayOfWeek(StartDate);

*// Using ISO week day number*

*// return ISODayOfWeek(StartDate);*

}**function** EndOfMonthDay (InputDate)

{

*// If the input parameter is omitted then current date is taken*

**if** (strictEqual(InputDate, undefined)) InputDate = aqDateTime.Today();

**let** DayNo = aqDateTime.GetDay(InputDate);

**let** MonthNo = aqDateTime.GetMonth(InputDate);

**let** YearNo = aqDateTime.GetYear(InputDate);

**let** EndDate = aqDateTime.AddDays(InputDate, - DayNo + DaysInMonth(MonthNo, YearNo));

*// Using US week day number*

**return** aqDateTime.GetDayOfWeek(EndDate);

*// Using ISO week day number*

*// return ISODayOfWeek(EndDate);*

}

### Converting to Date Object

JavaScript has the native `Date`

object that was created to hold date-time values and has its own methods to manage dates. A complete description of the object is in the Date Object article on the Mozilla Developer Network website. The sample code below demonstrates how to create this object.

JavaScript

**function** DateDemo()

{

*// Create Date object.*

**let** DateObj = **new** Date();

Log.Message(DateObj.toDateString());

**let** Day = DateObj.getDate();

**let** Month = DateObj.getMonth();

**let** Year = DateObj.getYear();

*// Note that the month number is zero-based*

Log.Message(Day + " day(s) have passed since the beginning of the " + (Month + 1) + " month of " + Year + " year.");

}

However the methods of the `aqDateTime`

object can only operate with the variant date-time values. To convert variant values to instances of the `Date`

object and vice versa you can use the following routines. The first one accepts the variant value as input parameter and returns the object instance and the second routine, on the contrary, accepts the object instance and returns variant.

JavaScript

**function** ToDateObject (InputDate)

{

*// Parse variant date onto components *

**let** Day = aqDateTime.GetDay(InputDate);

**let** Month = aqDateTime.GetMonth(InputDate);

**let** Year = aqDateTime.GetYear(InputDate);

*// Create Date object*

**let** DateObj = **new** Date();

*// Assign values to object*

DateObj.setDate(Day);

DateObj.setMonth(Month - 1);

DateObj.setFullYear(Year);

**return** DateObj;

}**function** ToVariantDate (InputDateObj)

{

**let** VariantDate = aqDateTime.SetDateElements(InputDateObj.getFullYear(), InputDateObj.getMonth() + 1, InputDateObj.getDate());

**return** VariantDate;

}

**Note: **The routines above only deal with the date portion. However the `Date`

object can store time values as well. To learn how to convert a variant value holding both date and time parts to the `Date`

object instance, see a similar section in the JavaScript - Working With Time Values topic.

### See Also

Working With Dates

JavaScript - Working With Time Values

aqDateTime Object