Implement the Geohashing algorithm proposed by xkcd.
Specifically, given the the Dow opening and a date in date object (optional), return the geohashing coordinates, using the following steps (adapted from explainxkcd, slightly modified):
- Take the provided date and convert it in the format
yyyy-mm-dd-at UTC time, then append the most recent opening value for the Dow Jones Industrial Average (supplied as an argument). Dow opening provided will always be accurate to 2 decimal places, but if it has less than 2 decimal digits, pad 0s on the right (12345 => 12345.00). If no dates are provided, use current time instead. - Pass this string through the MD5 algorithm, and output as a hexademical value.
- Divide the hash value into two 16 character halves, treat each half as base-16 decimal expansions (by appending
0.in the front, and convert them back to base 10, rounded to 6 decimal places. - Return the result coordinates as an array.
An example case straight out from the comic is provided:
Date: 2005-05-26, Dow opening: 10458.68
yyyy-mm-dd-dow: 2005-05-26-10458.68
MD5: db9318c2259923d08b672cb305440f97 => db9318c2259923d0 | 8b672cb305440f97
Coordinates (HEX): [0.db9318c2259923d0, 0.8b672cb305440f97]
Coordinates (DEC): [0.857713, 0.544543]Note: You don't have to worry about the 30W Time Zone Rule.