Benchmark: Date.now() vs new Date().getTime() 2

Script Preparation code:

var timestamp = null;

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Date.now()	4367697.5 Ops/sec
new Date().getTime();	3984675.5 Ops/sec

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

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The benchmark tests two different approaches to measuring time in JavaScript: `Date.now()` and `new Date().getTime()`. Let's break down what each approach is, their pros and cons, and some additional considerations.

**Approach 1: `Date.now()`**

`Date.now()` returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC) as a high-resolution timestamp. This method is generally faster and more efficient compared to using `new Date()` because it avoids the overhead of creating a new date object.

Pros:

* Fast execution speed
* Low overhead in terms of memory allocation and garbage collection

Cons:

* May return NaN (Not a Number) if the system clock is not set correctly
* Not suitable for measuring time intervals between specific events or timestamps

**Approach 2: `new Date().getTime()`**

This approach creates a new date object using `new Date()`, and then calls the `getTime()` method to get its timestamp in milliseconds. This method can be slower than `Date.now()` because of the overhead of creating and manipulating the date object.

Pros:

* Allows for more flexibility when measuring time intervals between specific events or timestamps
* Can provide a more precise timestamp due to the use of a dedicated date object

Cons:

* Slower execution speed compared to `Date.now()`
* Requires more memory allocation and garbage collection

**Other Considerations**

When choosing between these two approaches, consider the following factors:

* Performance-critical code: Use `Date.now()` for high-performance applications where every millisecond counts.
* Time interval measurements: Use `new Date().getTime()` when measuring time intervals between specific events or timestamps.
* Code readability and maintainability: If code readability is more important than performance, use `new Date().getTime()` for better clarity.

**Library Usage**

In the provided benchmark test case, there doesn't appear to be any external library usage. However, if a library were used, it would depend on the specific requirements of the project. For example:

* If a project required precise timekeeping and interval measurements, a library like Moment.js might be used.
* If a project focused on performance-critical code and needed the fastest possible execution speed, a lightweight library like Lodash's `performance.now()` function could be considered.

**Special JavaScript Features or Syntax**

This benchmark test case doesn't utilize any special JavaScript features or syntax beyond the two approaches being compared. However, if additional factors were to be taken into account, such as:

* Support for older browsers: A library like Modernizr could be used to detect browser support for newer JavaScript features.
* Error handling: Try-Catch blocks or other error-handling mechanisms might be employed depending on the specific requirements of the project.

**Alternatives**

If you're looking for alternatives to these approaches, consider:

* Using a dedicated timestamp library like Nanosecond.js for high-precision timing.
* Implementing your own timestamp mechanism using a combination of `Date.now()` and other performance-critical functions.
* Leveraging Web Workers or other concurrency models to measure performance in parallel.

Keep in mind that the choice of approach depends on the specific requirements of your project, and there is no one-size-fits-all solution.

Related benchmarks:

Date.now() vs new Date().getTime() 2 (version: 0)

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

Created: 6 months ago by: Guest

Jump to the latest result

Date.now()

new Date().getTime();

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):