Get An Epoch Timestamp In JavaScript

Epoch timestamps in JavaScript are the number of milliseconds that have elapsed since midnight on Jan. 1, 1970 UTC. I like using them because they are integers and are the same for any given time regardless of time zone.

They're also handy since they are what's returned from [TODO: Code shorthand span ] and [TODO: Code shorthand span ] on a ` Date ` .

The epoch in millisecond for current time is available with :

javascript

const epochTime = Date.now()

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Epoch in milliseconds for a specific time are obtained with :

javascript

const backToTheFuture = new Date('Oct 21, 2015 07:28:00 GMT+05:00').getTime()

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To pull the epoch based timestamp back into a string do something like :

javascript

const backToTheFutureString = new Date(backToTheFuture).toString()

Seconds Only

Some external tools provide epoch timestamps but they only go down to the second instead of the millisecond. If you need to coordinate with one of them, use this for the current time :

javascript

const epochTimeUnix = Math.round(Date.now() / 1000)

And this for a specific datetime :

javascript

const backToTheFutureUnix = Math.round(new Date('Oct 21, 2015 07:28:00 GMT+05:00').getTime() / 1000)

TODO : Add stuff about [TODO: Code shorthand span ]