Benchmark: Date.now() - Date.now() vs new Date() - new Date()

Script Preparation code:

var timedif = null;

Tests:

Date.now()
timedif = Date.now() - Date.now();
new Date().getTime();
timedif = 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

Autogenerated LLM Summary (model gemma2:9b, generated 27 days ago):

LLMs can make mistakes. Check important info.

This benchmark on MeasureThat.net compares the performance of two methods for calculating the time difference in JavaScript:

* **`Date.now()`**: This method returns the number of milliseconds that have elapsed since the Unix epoch (January 1, 1970, 00:00:00 UTC). 
* **`new Date().getTime()`**:  This creates a new `Date` object and then uses its `.getTime()` method to get the number of milliseconds since the Unix epoch.

**Breakdown:**

The benchmark code essentially performs these actions in both test cases:

1. **Creates a variable:** `timedif = null;` is used to store the calculated time difference.
2. **Performs the calculation:** 
    *  Test case 1: `timedif = Date.now() - Date.now();` This calculates the difference between the current time and itself, always resulting in 0.
    * Test case 2: `timedif = new Date() - new Date();` This creates two new `Date` objects and subtracts their timestamps.

**Pros & Cons:**

* **`Date.now()`**: 
    * **Pros**: This method is very efficient as it's a built-in function optimized for performance. It directly returns the milliseconds since the epoch without any additional object creation.
    * **Cons**: Can be limited if you need more precise time information than milliseconds or require specific date and time formatting.

* **`new Date().getTime()`**: 
    * **Pros**: Offers more flexibility as it allows access to other `Date` object methods for manipulating and formatting the timestamp (e.g., getting year, month, day, etc.).
    * **Cons**: Generally slower than `Date.now()`, as it involves creating a new `Date` object and then calling `.getTime()`

**Other Considerations:**

This benchmark highlights that  `Date.now()` is significantly faster for simple time difference calculations in JavaScript.

Let me know if you have any more questions about this or other benchmarks!

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/108.0.0.0 Safari/537.36

Browser/OS: Chrome 108 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Date.now()	3120973.5 Ops/sec
new Date().getTime();	2333698.2 Ops/sec

Related benchmarks:

Date.now() - Date.now() vs new Date() - new Date() (version: 0)

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

Created: one year 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 gemma2:9b, generated 27 days ago):