How do I get a timestamp in JavaScript?

Performance-wise precise timing

For situations that need millisecond precision, performance.now() is your guy. 👌 This is particularly helpful in performance benchmarking.

console.log(performance.now());
// Now measured with the precision of a Swiss watch
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Obtain Unix timestamp (in seconds)

To fetch the Unix timestamp in seconds, use Math.floor(Date.now() / 1000).

console.log(Math.floor(Date.now() / 1000));
// Unix time, in English: Number of seconds since 1970..., but who's counting? 🤓
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More methods to get milliseconds

While Date.now() is generally adequate, there are other techniques if you need clarity or have to deal with older browsers.

• Syntax wizardry: For quick conversion to milliseconds.

console.log(+new Date()); 
// Just add a plus, because every little helps!
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• Spelling it out: Clarity counts.

console.log(new Date().getTime()); 
// Because sometimes, you need to spell it out.
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• Supporting the ancients: When dealing with older IE versions.

if (!Date.now) {
  Date.now = function() { return new Date().getTime(); };
}
// Because ES5 is for cool kids and IE is the awkward cousin at the family dinner 🤷‍♂️
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Measure time from page load

Discern the time that has elapsed since the webpage loaded using performance.timing.navigationStart + performance.now().

console.log(performance.timing.navigationStart + performance.now());
// It's been HOW long since this page loaded?😮
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Short and sweet Unix timestamp

If brevity and speed matters to you, here's a concise Unix timestamp formulation:

console.log(Date.now() / 1000 | 0);
// Nothing to see here, just ninja skills!
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Handling time in JavaScript

Working with time in JavaScript might be a bit different from other languages. Here's what you need to know:

• JavaScript and Unix do not use the same units for timestamps.
• JavaScript uses milliseconds.
• Unix, on the other hand, uses seconds.

Advanced techniques and cross-compatibility

Getting a timestamp might be simple, but there are advanced techniques and considerations.

• jQuery equivalent: Use $.now() to get current millisecond count.

console.log($.now());
// jQuery got your back if JavaScript seems too mainstream. 😎
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• Calculate relative time: Create your own function.

const startTime = Date.now();
const relativeTime = () => Date.now() - startTime;
console.log(relativeTime());
// Because who doesn't want their own, personal timestamp? 💁‍♂️
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• Fast and furious: For the coder in a hurry - the bitwise OR |0.

console.log(Date.now() / 1000 | 0);
// Only advisable when racing against Vin Diesel 🚗💨
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• Harmony in coding languages: When you need to sync with server time like PHP.

console.log(Math.floor(Date.now() / 1000));
// 🙏 Pray to the gods of sync where milliseconds and seconds harmonize.
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• Always take into consideration the potential risks involved with quick and ingenious methods.