Benchmark: Date.now() vs new Date().getTime() vs performance.measure()

Script Preparation code:

let start = null;
let end = null;

Tests:

Date.now()
start = Date.now(); end = Date.now();
new Date().getTime();
start = new Date().getTime(); end = new Date().getTime();
performance.now()
start = performance.now() end = performance.now()
performance.measure
performance.mark('start') start = Date.now() const { duration } = performance.measure('span', 'start') end = start + duration

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Date.now()
new Date().getTime();
performance.now()
performance.measure

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Date.now()	3113929.5 Ops/sec
new Date().getTime();	2866913.5 Ops/sec
performance.now()	2138284.2 Ops/sec
performance.measure	600766.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and the pros and cons of each approach.

**Benchmark Overview**

The test compares four different ways to measure time in JavaScript:

1. `Date.now()`
2. `new Date().getTime()`
3. `performance.now()`
4. `performance.measure()`

**Comparison Options**

Here's a brief overview of what's being compared for each option:

1. **`Date.now()`**: This method returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC). It's a simple and widely supported method but can be affected by system clock drift.
2. **`new Date().getTime()`**: Similar to `Date.now()`, this method returns the timestamp in milliseconds since January 1, 1970, 00:00:00 UTC. However, it also takes into account time zones and daylight saving time (DST) rules.
3. **`performance.now()`**: This method is more accurate than `Date.now()` or `new Date().getTime()` because it uses the operating system's high-resolution timer. It returns the number of milliseconds since the Unix Epoch, but with higher precision.
4. **`performance.measure()`**: This method uses a specialized API to measure time intervals between two markers. It provides more accurate results than other methods, especially for shorter intervals.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **`Date.now()`**
	* Pros: simple, widely supported
	* Cons: can be affected by system clock drift, less accurate than other options
2. **`new Date().getTime()`**
	* Pros: more accurate than `Date.now()` due to time zone and DST considerations
	* Cons: may still have some impact from system clock changes or DST transitions
3. **`performance.now()`
	* Pros: high-resolution timer, most accurate option
	* Cons: only available in modern browsers (Chrome 112 and later)
4. **`performance.measure()`**
	* Pros: provides accurate results even for short intervals, less dependent on system clock drift
	* Cons: requires more complex setup, may not be supported by all browsers

**Library Usage**

There is no explicit library usage mentioned in the benchmark definition or test cases.

**Special JS Features/Syntax**

None of the provided options rely on special JavaScript features or syntax. However, `performance.now()` and `performance.measure()` are part of the Web Performance API, which may require additional setup or configuration for some browsers.

**Alternatives**

If you're looking for alternative methods to measure time in JavaScript, consider:

1. **`requestAnimationFrame()`**: This method uses a callback function to measure the passage of time between two animation frame events.
2. **`setInterval()`**: This method uses a timer to execute a function at regular intervals, which can be used to measure time.
3. **`setTimeout()`**: Similar to `setInterval()`, but executes a single function after a specified delay.

Keep in mind that each of these alternatives has its own pros and cons, and may not offer the same level of accuracy or precision as the methods compared in this benchmark.

Related benchmarks:

Date.now() vs new Date().getTime() vs performance.measure() (version: 0)

Comparing performance of: Date.now() vs new Date().getTime(); vs performance.now() vs performance.measure

Created: one year ago by: Guest

Jump to the latest result

Date.now()

new Date().getTime();

performance.now()

performance.measure

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):