Benchmark: Date.now() vs new Date().getTime() vs performance.now() vs Date().toString();

Script Preparation code:

var timestamp = null;

Tests:

Date.now()
timestamp = Date.now();
new Date().getTime();
timestamp = new Date().getTime();
performance.now()
timestamp = performance.now()
Date().toString();
timestamp = Date.toString();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

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/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Mac OS X 10.15.7

View result in a separate tab

Date.now()

10.1M/s

new Date().getTime();

9.0M/s

Date().toString();

2.6M/s

performance.now()

2.2M/s

View exact numbers

Test name	Executions per second
✓ Date.now()	10,108,631 Ops/sec
new Date().getTime();	8,972,277 Ops/sec
Date().toString();	2,582,362 Ops/sec
performance.now()	2,196,340 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided JSON benchmark.

**Benchmark Purpose**

The benchmark is designed to compare the performance of different methods for getting the current timestamp in JavaScript:

1. `Date.now()`
2. `new Date().getTime()`
3. `performance.now()`
4. `Date().toString()` (which returns a string representation of the date)

**Options Compared**

Each option is compared to measure their execution speed, expressed as the number of executions per second.

* `Date.now()` and `new Date().getTime()` both return the timestamp in milliseconds since the Unix epoch (January 1, 1970). However, they differ in implementation:
	+ `Date.now()` uses the internal representation of the date object.
	+ `new Date().getTime()` creates a new `Date` object and returns its current timestamp.
* `performance.now()` returns the timestamp in milliseconds since the performance timer was started. It's designed for measuring time intervals.
* `Date().toString()` returns a string representation of the date in the format `Fri Jan 01 1970 00:00:00 GMT-0600`. This is not suitable for measuring execution speed.

**Pros and Cons**

Here are some pros and cons of each option:

1. `Date.now()`:
	* Pros: Fast, low overhead.
	* Cons: May be affected by clock skew (the difference between the system's clock and the actual time).
2. `new Date().getTime()`:
	* Pros: Easy to understand, widely supported.
	* Cons: Creates a new object, which can incur additional overhead.
3. `performance.now()`:
	* Pros: Designed for measuring time intervals, accurate.
	* Cons: May be slower due to the overhead of the performance timer.
4. `Date().toString()`:
	* Pros: Simple, easy to read.
	* Cons: Not suitable for measuring execution speed.

**Library and Special JS Features**

None of the tested options rely on a specific library or special JavaScript features (like async/await, destructuring, etc.).

**Other Alternatives**

Other alternatives for getting the current timestamp in JavaScript include:

1. `Date.UTC()`: Returns the timestamp in UTC (Coordinated Universal Time).
2. `new Date().toISOString()`: Returns the date and time as a string in ISO format.
3. `performance.now()` with the `HighPerformanceDate` API (supported in modern browsers).

These alternatives may have different performance characteristics or requirements for usage.

**Benchmark Preparation Code**

The provided preparation code is minimal:
```javascript
var timestamp = null;
```
It only initializes a variable `timestamp`, which will be used to store the result of each benchmarking function.

Date.now() vs new Date().getTime() vs performance.now() vs Date().toString(); (version: 0) Benchmark.js

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

Created: 4 years ago by: Guest

Go to the latest result

Date.now()

new Date().getTime();

performance.now()

Date().toString();

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Date.now() vs new Date().getTime() vs performance.now() vs Date().toString(); (version: 0) Benchmark.js

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

Created: 4 years ago by: Guest

Go to the latest result

Date.now()

new Date().getTime();

performance.now()

Date().toString();

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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