Benchmark: new Date vs Date.now

Tests:

new Date
new Date();
Date now
Date.now();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Date
Date now

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**What is tested?**

The provided JSON represents two benchmark test cases that compare the performance of `new Date()` and `Date.now()` in JavaScript.

These functions are used to obtain the current date and time. The main difference between them lies in how they handle dates:

*   `new Date()`: Creates a new `Date` object, which is initialized with the current date and time based on the system clock.
*   `Date.now()`: Returns the number of milliseconds since the Unix Epoch (January 1, 1970, 00:00:00 UTC) as a 32-bit integer.

**Options compared**

The benchmark compares two options:

1.  **Using `new Date()`**: This approach creates a new `Date` object and returns its value.
2.  **Using `Date.now()`**: This approach directly returns the number of milliseconds since the Unix Epoch.

**Pros and Cons**

*   Using `new Date()`: Pros:
    *   Can handle dates in different formats (e.g., UTC, local timezones).
    *   More flexible for date calculations.
Cons:
    *   Creates a new object on every call, which can be expensive in terms of memory allocation and garbage collection.
*   Using `Date.now()`: Pros:
    *   Directly returns the number of milliseconds since the Unix Epoch, eliminating the need to create an object.
Cons:
    *   Only returns the time in seconds since the Unix Epoch (not accounting for fractional parts).
    *   May not be suitable for date calculations requiring timezone conversion.

**Other considerations**

*   **Memory allocation**: Creating a new `Date` object on every call using `new Date()` can lead to memory allocation and garbage collection overhead, making it slower than using `Date.now()`.
*   **Precision**: `Date.now()` returns the number of milliseconds since the Unix Epoch as a 32-bit integer, which may lose precision for very large numbers.
*   **Browser support**: Both functions are widely supported across modern browsers.

**Library usage**

In this benchmark, no libraries are explicitly used. The JavaScript `Date` and `Date.now()` functions are built-in and part of the ECMAScript standard.

**Special JS features or syntax**

There are no special JS features or syntax mentioned in this benchmark. It focuses solely on comparing the performance of two basic date-time-related functions.

If you're interested in exploring more advanced date-time-related concepts, you might want to consider libraries like Moment.js or Luxon, which provide more robust and flexible date manipulation capabilities.

**Alternatives**

To create similar benchmarks, you can explore other options:

1.  **Test frameworks**: Use a test framework like Jest or Mocha to write and run tests.
2.  **Benchmarking libraries**: Utilize libraries like Benchmark.js or Microbenchmark to create and compare benchmark results.
3.  **Web performance tools**: Leverage Web Performance Tools like Chrome DevTools' Performance tab or Firefox's Performance Monitoring Tool to analyze and optimize your web applications.

By understanding these alternatives, you can extend your benchmarking capabilities and explore more advanced testing techniques.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:93.0) Gecko/20100101 Firefox/93.0

Browser/OS: Firefox 93 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
new Date	5730897.5 Ops/sec
Date now	8563364.0 Ops/sec

Related benchmarks:

new Date vs Date.now (version: 0)

Comparing performance of: new Date vs Date now

Created: 3 years ago by: Guest

Jump to the latest result

new Date

Date now

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):