dni-date-converter

The D'ni Date Converter is a JavaScript D'ni↔Gregorian calendar conversion algorithm, based on the D'ni Clock script created by Jehon the Scribe, RIUM+, and rokama. Additional content drawn from algorithms created by Brett Middleton.

This project contains both the converter and a website which can be used to convert arbitrary dates between the two calendar systems. To use the date converter in your own project, you will only need js/DniDate.js.

DniDate Object

DniDate is modeled stylistically on the native JavaScript Date object, with similar getters and setters for the various components of a D'ni date. It also supports manipulation of D'ni dates, just as the Date object supports manipulating dates in the Gregorian calendar.

Initialization

new DniDate();
new DniDate(hahr[, vailee[, yahr[, gartahvo[, tahvo[, gorahn[, prorahn]]]]]]);

If no arguments are provided, the constructor creates a DniDate object for the current D'ni date and time.

If at least one argument is provided, missing arguments are either set to 1 (for the yahr, if missing), or 0 for all others.

If a value falls outside of the valid range for that argument, the adjacent value will be adjusted. For instance, new DniDate(2500, 10, 1) is equivalent to new DniDate(2501, 0, 1) – both create a date for Leefo 1, 2501. This auto-adjustment applies to all arguments besides hahr.

Examples

var dd = new DniDate(9672, 8, 3, 2, 5, 20, 12); // Leevosahn 3 9672 DE 2:05:20:12
var dd = new DniDate(9672, 8, 3); // Leevosahn 3 9672 DE 0:00:00:00
var dd = new DniDate(9672); // Leefo 1 9672 DE 0:00:00:00
var dd = new DniDate(); // Date will be set to the current D'ni date and time

Instance methods

Converters

setFromSurfaceDate(dateObject[, isUTC])

Sets the DniDate object to the D'ni date and time that matches the supplied JavaScript Date object. By default, the time of the specified date is converted to Cavern Time (UTC-0700) before being converted. If you want the time of your specified date to be treated as UTC by the converter, set the isUTC parameter to true.

NOTE: If you try to create a Gregorian date between 1 CE and 99 CE (1 - 99) by calling new Date(year, month, day), the Date object will "helpfully" set your date in the 20th century (1901 - 1999). To avoid this, create the Date object, then call setFullYear() with your desired year before passing it into DniDate:

var surfaceDate = new Date(47, 0, 1); // January 1, 1947
surfaceDate.setFullYear(47); // January 1, 0047

var dd = new DniDate();
dd.setFromSurfaceDate(surfaceDate);

toSurfaceDate()

Returns a new Date object set to the Gregorian calendar equivalent of the DniDate's date and time. The time of this object is aligned so that calling .toUTCString() will provide the proper UTC time, and adjusting the value down by 7 hours will provide the proper D'ni Cavern date.

toCavernDateTimeString()

Returns a full date and time string containing the Gregorian equivalent of the configured D'ni date in the Cavern's local time zone (UTC-0700).

Getters

• getHahr()
• getVailee() (Returns a value between 0 and 9 representing the numerical vailee value.)
• getVaileeName([useDniFontMapping]) (Returns the actual vailee name as a string value. When useDniFontMapping is true, the output can be mapped to the webfont version of Cyan's Dnifont font. When useDniFontMapping is false, the output is written in OTS. The default value for useDniFontMapping is false.)
• getYahr()
• getGartahvo()
• getPartahvo() (Not commonly used; this value divides the D'ni yahr into 5 segments, rather than the tahvo's 25.)
• getTahvo()
• getGorahn()
• getProrahn()

Setters

• setHahr()
• setVailee() (Uses 0-indexed values.)
• setGartahvo()
• setTahvo()
• setGorahn()
• setProrahn()

As with the constructor, if you supply a value that falls outside of the valid range for that date component via one of these setters, a valid date will automatically be calculated by adjusting adjacent values.

You may notice that there is a getPartahvo(), method, but no setPartahvo() method. This is because DniDate treats the partahvo as a calculated unit, rather than a specified one. The value of the partahvo in a given date is determined by dividing the number of tahvotee by 5, then rounding down, resulting in an integer value between 0 and 4.

Formatters

toDateString([useDniFontMapping])

Returns a string with the vailee name, yahr, and hahr (month, day, year), as well as the era (BE or DE). When useDniFontMapping is set to true, the vailee name will be formatted to display properly in conjunction with Cyan's Dnifont font. Otherwise, it will use the capitalized OTS transliteration.

toTimeString()

Returns the gartahvo, tahvo, gorahn, and prorahn, separated by colons. The tahvo, gorahn, and prorahn values are zero-padded to two digits in this output for better legibility.

toString()

Overrides the default Object behavior and returns a single string with both date and time values, concatenated together by a space.

toFontMappedString()

Outputs the same content as toString(), but with the vailee formatted to display properly in conjunction with Cyan's Dnifont font.

valueOf()

Automatically converts the date to Gregorian time and outputs the built-in Date() object's valueOf() value, which is the number of milliseconds between 1 January 1970 00:00:00 UTC and the given date.

Dealing with timezones

Converting to D'ni Time

D'ni has only one timezone, which is aligned to UTC-0700 (Mountain Standard Time). Daylight Saving Time does not apply in D'ni, so during the summer, the offset remains UTC-0700. When converting a surface date to D'ni time using setFromSurfaceDate(), the Date object will be converted to UTC-0700. This means that 1/1/1900 12:00:00 UTC-0800 and 1/1/1900 12:00:00 UTC-0700 will return different D'ni dates, while 1/1/1900 12:00:00 UTC-0700 and 1/1/1900 13:00:00 UTC-0800 will return the same D'ni date.

Converting to Surface Time

The surface dates returned by toSurfaceDate() are aligned to the UTC (Coordinated Universal Time) timezone, which is GMT with no daylight saving offset. To display dates in the user's local timezone, simply call one of the Date object's conversion getters (such as toString()) or assemble the date manually using the getters for each individual date component. You can also pass this Date object to a date formatting tool like moment.js.

Displaying Cavern-local time (UTC-0700)

Use this code snippet to get a date object that is aligned to Mountain Standard Time, where the D'ni cavern is located:

var dd = new DniDate(2500, 7, 21);
var surfaceUtc = dd.toSurfaceDate();
var cavernLocal = new Date(surfaceUtc.getTime() - (7 * 3600000));