Benchmark: Date.now() __vs__ new Date().getTime()

Script Preparation code:

var timestamp = null;

Tests:

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

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: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1.1 Safari/605.1.15

Browser/OS: Safari 14 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Date.now()	2766303.2 Ops/sec
new Date().getTime();	2680408.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark definition and test cases.

**Benchmark Definition:**
The benchmark is defined by two scripts that measure the performance of different ways to get the current timestamp:

1. `timestamp = Date.now();`
2. `timestamp = new Date().getTime();`

Both scripts initialize a variable `timestamp` and then use it, but they differ in how they get the initial value for this variable.

**Options Compared:**

*   **Date.now()**: This method returns the number of milliseconds since the Unix epoch (January 1, 1970, 00:00:00 UTC).
*   **new Date().getTime()**: This method also returns the number of milliseconds since the Unix epoch. However, it uses a different internal implementation to calculate this value.

**Pros and Cons:**

*   **Date.now():**
    *   Pros:
        *   Widely supported across most browsers and Node.js environments.
        *   Returns milliseconds since the last time `Date.now()` was called (not just when the epoch began).
    *   Cons:
        *   Not necessarily more accurate than other methods, especially in older browsers or environments with specific timing implementations.

*   **new Date().getTime():**
    *   Pros:
        *   More accurately reflects the system's current time.
    *   Can be useful for systems where millisecond precision is required (e.g., audio/video processing).
    *   Returns milliseconds since the epoch, just like `Date.now()`.
    *   Cons:
        *   Less supported across browsers and Node.js environments due to its usage of internal date calculations.

**Library:**
None

**Special JS Feature/Syntax:**
There are no special features or syntax being tested here. Both `Date.now()` and `new Date().getTime()` utilize standard JavaScript methods for calculating timestamps.

**Alternative Approaches:**

*   **Using a global variable (`performance.now()`):** If you want to measure time intervals in a specific scope, consider using the `performance.now()` method provided by modern browsers. This approach returns high-resolution timestamp values accurate up to 1/30th of a second.
*   **Utilizing Web Workers:** For CPU-bound tasks or performance comparisons with multiple inputs, you may need to use Web Workers (if your environment supports it). Web Workers allow you to execute JavaScript in separate threads for parallel execution of long-running operations without impacting the main thread.

When choosing between `Date.now()` and `new Date().getTime()`, consider the specific requirements of your application. If high accuracy is necessary, or if only milliseconds are required since the last call to either function, `new Date().getTime()` would provide that.

Related benchmarks:

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

timestamps perfs

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

Created: 5 years ago by: Registered User

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):

Date.now() __vs__ new Date().getTime() (version: 0)

timestamps perfs

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

Created: 5 years ago by: Registered User

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):

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