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

Script Preparation code:

var timestamp = null;

Tests:

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

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

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

**Overview**

The benchmark compares the performance of three different ways to get the current timestamp in JavaScript:

1. `+new Date`
2. `Date.now()`
3. `new Date().getTime()`

These methods are used to measure the performance of these approaches, which can be useful for optimizing code that relies on timestamping.

**What's being tested**

The benchmark is testing the execution speed of each approach:

* `+new Date`: This method uses the unary plus operator (`+`) to coerce the result to a number. The `Date` constructor returns an object with various properties, and the `+` operator is used to extract only the numeric value.
* `Date.now()`: This method directly calls the `now()` function on the `Date` object, which returns the number of milliseconds since the Unix epoch (January 1, 1970, 00:00:00 UTC).
* `new Date().getTime()`: This method creates a new `Date` object and then calls the `getTime()` method to get the timestamp.

**Options compared**

The benchmark is comparing the performance of these three approaches:

Pros and cons of each approach:

1. `+new Date`:
	* Pros: Simple and straightforward, doesn't require creating an object.
	* Cons: Can be slower due to the coercion operation.
2. `Date.now()`:
	* Pros: Fast and efficient, as it directly calls a function on the `Date` object.
	* Cons: May not work correctly in older browsers or with certain types of dates (e.g., dates from other time zones).
3. `new Date().getTime()`:
	* Pros: Accurate and reliable, as it creates a new date object and then gets the timestamp.
	* Cons: Can be slower due to the creation of an unnecessary `Date` object.

**Library or special JavaScript feature**

None of these methods use any external libraries or special JavaScript features. They are all built-in properties or functions of the JavaScript language.

**Other considerations**

When choosing between these approaches, consider the following:

* If you need a simple and straightforward way to get a timestamp, `+new Date` might be sufficient.
* If you prioritize performance and don't care about older browsers, `Date.now()` is likely your best choice.
* If accuracy and reliability are crucial, especially for dates from other time zones or in older browsers, `new Date().getTime()` is the safest bet.

**Alternatives**

If you're looking for alternative approaches, consider the following:

1. `performance.now()`: This method provides high-resolution timestamps on modern browsers and is often preferred over `Date.now()`.
2. `Intl.DateTimeFormat`.options.minimumHours` / `Intl.DateTimeFormat().resolvedOptions().minimumHours`: These methods provide a more robust way to get accurate timestamps, especially for dates from other time zones.
3. `window performance`: This API provides high-resolution timing and is supported by most modern browsers.

In summary, the benchmark provides a good starting point for comparing the performance of different approaches to getting the current timestamp in JavaScript.

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/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
+new Date	1953099.6 Ops/sec
Date.now()	2839215.2 Ops/sec
new Date().getTime();	2532206.8 Ops/sec

Related benchmarks:

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

Comparing performance of perfomance.now, Date.now and new Date().getTime()

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

Created: 3 years ago by: Guest

Jump to the latest result

+new Date

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 29 days ago):