javascript unix timestamp

stackoverflow.com › questions › 221294 › how-do-i-get-a-timestamp-in-javascript

Timestamp in milliseconds

To get the number of milliseconds since Unix epoch, call Date.now:

Date.now()

Alternatively, use the unary operator + to call Date.prototype.valueOf:

+ new Date()

Alternatively, call valueOf directly:

new Date().valueOf()

To support IE8 and earlier (see compatibility table), create a shim for Date.now:

if (!Date.now) {
    Date.now = function() { return new Date().getTime(); }
}

Alternatively, call getTime directly:

new Date().getTime()

Timestamp in seconds

To get the number of seconds since Unix epoch, i.e. Unix timestamp:

Math.floor(Date.now() / 1000)

Alternatively, using bitwise-or to floor is slightly faster, but also less readable and may break in the future (see explanations 1, 2):

Date.now() / 1000 | 0

Timestamp in milliseconds (higher resolution)

Use performance.now:

var isPerformanceSupported = (
    window.performance &&
    window.performance.now &&
    window.performance.timing &&
    window.performance.timing.navigationStart
);

var timeStampInMs = (
    isPerformanceSupported ?
    window.performance.now() +
    window.performance.timing.navigationStart :
    Date.now()
);

console.log(timeStampInMs, Date.now());

Answer from daveb on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 221294 › how-do-i-get-a-timestamp-in-javascript

datetime - How do I get a timestamp in JavaScript? - Stack Overflow

Timestamp in milliseconds

To get the number of milliseconds since Unix epoch, call Date.now:

Date.now()

Alternatively, use the unary operator + to call Date.prototype.valueOf:

+ new Date()

Alternatively, call valueOf directly:

new Date().valueOf()

To support IE8 and earlier (see compatibility table), create a shim for Date.now:

if (!Date.now) {
    Date.now = function() { return new Date().getTime(); }
}

Alternatively, call getTime directly:

new Date().getTime()

Timestamp in seconds

To get the number of seconds since Unix epoch, i.e. Unix timestamp:

Math.floor(Date.now() / 1000)

Alternatively, using bitwise-or to floor is slightly faster, but also less readable and may break in the future (see explanations 1, 2):

Date.now() / 1000 | 0

Timestamp in milliseconds (higher resolution)

Use performance.now:

var isPerformanceSupported = (
    window.performance &&
    window.performance.now &&
    window.performance.timing &&
    window.performance.timing.navigationStart
);

var timeStampInMs = (
    isPerformanceSupported ?
    window.performance.now() +
    window.performance.timing.navigationStart :
    Date.now()
);

console.log(timeStampInMs, Date.now());

2 of 16

642

I like this, because it is small:

+new Date

I also like this, because it is just as short and is compatible with modern browsers, and over 500 people voted that it is better:

Date.now()

30 Seconds of Code

30secondsofcode.org › home › javascript › date › date to unix timestamp

Convert between a JavaScript Date object and a Unix timestamp - 30 seconds of code

January 7, 2024 - This means that you can convert between Date objects and Unix timestamps by dividing or multiplying by 1000. const toTimestamp = date => Math.floor(date.getTime() / 1000); const fromTimestamp = timestamp => new Date(timestamp * 1000); ...

Discussions

Add Unix Timestamp and Javascript Timestamp converstions to the date/time app - Feature Requests - n8n Community

I suggest adding two to easily convert Unix and Javascript timestamps. My use case: I’m exporting Zillow API data and all the listing date/times and change date/times are in Unix Time Stamp (aka milliseconds) Example: listingDateTimeOnZillow: 1699724220000. More on community.n8n.io

community.n8n.io

January 10, 2024

How can I convert "2020-11-18-05:12" into unix timestamp? and then add 5 hours to it?

Prerequisite: dealing with dates and times in programming is one of the most non-trivial things you can ever undertake. Until the JS standard library can handle date-time in a sane manner, seriously consider using a library like Luxon instead of trying to wrangle time on your own! You should generally allow the browser to calculate the local time, instead of changing the timestamp. Let's break down why. First, to get the ms from epoch: const dateTimeString = '2020-11-18-05:12' const [years, months, days, hours, minutes, seconds = 0, ms = 0] = dateTimeString.split(/[-:]/).map(n => +n) const unixDate = new Date(years, months - 1, days, hours, minutes, seconds, ms).valueOf() If you take that number, add 18,000,000 to it (5hrs in ms), then pass that number back into the Date constructor, you will find that the time is now wrong by 5 hours. This is because the Date constructor assumes all dates are entered in UTC, and will automatically use the timezone of the local machine to display the appropriate time (assuming that is what you are trying to accomplish). Also assuming that all you want is to display that time string in the user's local time, just remove the .valueOf() and you have a timezone appropriate Date object. As an aside, that string is almost an ISO 8601-1:2019 compliant date-time string, 2020-11-18T05:12:00, which can be converted directly with the Date constructor. Edit: A better way to offset the time, is to use a date-time+timezone string: const dateTimeString = '2020-11-18-05:12' const offset = '+05:00' const [years, months, days, hours, minutes, seconds = '00', ms = '000'] = dateTimeString.split(/[-:]/) const date = new Date(`${years}-${months}-${days}T${hours}:${minutes}:${seconds}.${ms}${offset}`) More on reddit.com

r/learnjavascript

November 18, 2020

converting the Unix Timestamp with GTM

There are lots of articles online about converting a Unix timestamp into date format using JavaScript - see e.g. this: https://coderrocketfuel.com/article/convert-a-unix-timestamp-to-a-date-in-vanilla-javascript You can do all the code in a Custom JavaScript variable. Simo More on reddit.com

r/GoogleTagManager

September 29, 2020

How to convert a future date into unix timestamp in JavaScript?

new Date(2020,12,12,12,30).getTime() would suffice ie. new Date(year,month,date,hour,min,sec,ms) More on reddit.com

r/learnjavascript

December 22, 2018

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