Convert ISO8601 date to epoch format (unix timestamp)

Question

How do I convert ISO 8601 date (ex. 20140107) to Unix timestamp (ex. 1389120125) using javascript?

Solution

If you're using a browser with ECMAscript 5 support, Date.parse() accepts an ISO-8601 datestring and returns an epoch value in milliseconds, so just divide that by 1000 and you're done.

However

Contrary to what you state, your input string doesn't conform to the ISO-8601 subset defined in ECMAscript because it's lacking the dashes between the individual fields. As far as I know, the dashes are mandatory for EMCAscript (even though ISO 8601 itself allows the dashless, or basic, format). So maybe you'll have to do some string parsing and use one of Date's constructors and its getTime() method to obtain the same

new Date(year, month [, day, hour, minute, second, millisecond]);

If you want to remain compatible with older browsers but still use Date.parse, you could consider including this shim

Comments

[Steve]

Thanks for your answer. I tried Date.parse(20140107); and got NaN. Any ideas why it is not working?

[fvu]

@Steve that's exactly the issue I tried to explain in my answer, plus a bonus one: you have to pass that variable as a string, otherwise it will be seen as a number. However Javascript does not support the basic, dash-less representation of dates meaning that Date.parse("2014-01-07") will work whereas Date.parse("20140107") won't. If you're stuck with the latter some string parsing will be required.

[Steve]

@fvu thanks for the explanation. I appreciate it. :)