Benchmark: Date.now() vs now()

Script Preparation code:

var now = Date.now;

function now2() {
  return Date.now();
}

Tests:

Date.now()
Date.now();
now()
now();
now2();
now2();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Date.now()
now()
now2();

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark results and provide insights into what's being tested.

**Benchmark Description**

The benchmark is designed to compare three different ways of accessing the current time in JavaScript: `Date.now()`, `now()` (not a built-in JavaScript function, but rather a custom function defined in the "Script Preparation Code"), and `now2()` (another custom function).

**Options Compared**

The benchmark compares the performance of these three methods:

1. `Date.now()`: This is a built-in JavaScript function that returns the number of milliseconds since the Unix epoch (January 1, 1970, 00:00:00 UTC).
2. `now()`: This is a custom function defined in the "Script Preparation Code" of the benchmark. It simply calls `Date.now()` internally.
3. `now2()`: This is another custom function defined in the "Script Preparation Code". Its implementation is not shown, but it's likely similar to `now()`.

**Pros and Cons**

Here are some pros and cons of each approach:

1. `Date.now()`:
	* Pros: It's a built-in function that provides accurate timekeeping.
	* Cons: It may have performance overhead due to the browser's internal calculations.
2. `now()` and `now2()`:
	* Pros: They are custom functions that can be optimized for performance, as they don't involve any external calculations.
	* Cons: If not implemented correctly, they could introduce subtle performance issues or even security vulnerabilities.

**Library Usage**

In this benchmark, there is no explicit library usage. However, some browsers may use internal libraries or frameworks that provide `Date.now()` functionality. For example, Chrome uses the WebKit engine's `kJSDateTime` module to implement `Date.now()`. If a custom implementation of `now()` or `now2()` is used, it may not be compatible with all browsers.

**Special JavaScript Features or Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark. However, some benchmarks might use advanced features like async/await, Promises, or Web Workers to compare performance under different execution contexts.

**Other Alternatives**

If you wanted to write a similar benchmark, you could consider adding more test cases, such as:

* Comparing the performance of `Date.now()` with other time-related functions, like `performance.now()` or `performance.timing`.
* Testing the performance of custom functions that use different algorithms for calculating the current time.
* Adding additional variables, like caching or memoization, to see how they affect the performance of each function.

Keep in mind that writing a high-quality benchmark requires careful consideration of factors like execution frequency, context switching, and memory allocation.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36

Browser/OS: Chrome 84 on Windows

View result in a separate tab

Test name	Executions per second
Date.now()	2689769.2 Ops/sec
now()	3657883.0 Ops/sec
now2();	1955204.4 Ops/sec

Related benchmarks:

Date.now() vs now() (version: 1)

Comparing performance of: Date.now() vs now() vs now2();

Created: 8 years ago by: Registered User

Jump to the latest result

Date.now()

now()

now2();

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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