How can I get seconds since epoch in Javascript?

Question

On Unix, I can run date \'+%s\' to get the amount of seconds since epoch. But I need to query that in a browser front-end, not back-end.

Is there a way

Answer 1

The above solutions use instance properties. Another way is to use the class property Date.now:

var time_in_millis = Date.now();
var time_in_seconds = time_in_millis / 1000;

If you want time_in_seconds to be an integer you have 2 options:

a. If you want to be consistent with C style truncation:

time_in_seconds_int = time_in_seconds >= 0 ?
                      Math.floor(time_in_seconds) : Math.ceil(time_in_seconds);

b. If you want to just have the mathematical definition of integer division to hold, just take the floor. (Python's integer division does this).

time_in_seconds_int = Math.floor(time_in_seconds);