.Net Ticks to ISO 8601 Date format using JavaScript

Question

I am saving DateTimeOffset object in MongoDB. Mongo driver serilizes DateTimeOffset as following.

[635519027206007023,0]

I need it to be converted to ISO 8601 format as follows.

2015-02-02T01:43:19+05:00

Conversion can be easily done using help of .NET DateTimeOffset class. But, in this case I am retrieving DateTimeOffset directly from MongoDB using JavaScript (Node.js). Hence I end up retrieving array of long.

How can I convert array of longs [635519027206007023,0] to ISO 8601 format 2015-02-02T01:43:19+00:00 using JavaScript ?

Answer 1

The epoch for the DateTimeOffset type is 0000-01-01, while the epoch for Javascript dates is 1970-01-01.

The DateTimeOffset ticks value for the date 1970-01-01 is 621355968000000000, so you can just subtract that from the value to convert it to the Javascript epoch.

Ticks in DateTimeOffset is 1/10000000 second, while ticks in Javascript dates is 1/1000 second, so divide the value by 10000 to convert it to Javascript date ticks.

So, to get the Javascript date from the DateTimeOffset ticks:

new Date((date[0] - 621355968000000000) / 10000)

Then you can use the toISOString method to convert the date to an ISO8601 string.