Benchmark: new-date-vs-date-settime

Script Preparation code:

var date = new Date();

var now = Date.now();
var nums = [];
for (var i = 0; i < 1000; i++) {
	nums[i] = now + i;
}

Tests:

new Date()
var len = nums.length; var d; for (var i = 0; i < len; i++) { d = new Date(nums[i]); }
setTime()
var len = nums.length; var d = reuse_date; for (var i = 0; i < len; i++) { d.setTime(nums[i]); }
BASE
var len = nums.length; var d; for (var i = 0; i < len; i++) { d = nums[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Date()
setTime()
BASE

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its options.

**Benchmark Overview**

The benchmark measures the performance of three different approaches for creating new Date objects in JavaScript:

1. `new Date()`
2. `setTime()` with an existing Date object
3. A "BASE" approach that simply assigns a value to a variable, which is not directly related to creating a new Date object

**Options Compared**

The benchmark compares the performance of these three approaches on a large dataset (`nums`) created using the following preparation code:
```javascript
var date = new Date();
var now = Date.now();
var nums = [];
for (var i = 0; i < 1000; i++) {
  nums[i] = now + i;
}
```
Each test case uses this setup to create a large array of numbers, and then iterates over the array to create new Date objects using the different approaches.

**Approach Options**

### `new Date()`

This approach creates a new Date object directly from scratch. It is likely the fastest option since it only requires a single call to the constructor function.

Pros:

* Fastest option
* Simple and straightforward

Cons:

* May require additional processing time for internal calculations, such as parsing the date string

### `setTime()` with an existing Date object

This approach uses the `setTime()` method on an existing Date object (`reuse_date`) to set the timestamp. This may be slower than the `new Date()` approach since it requires accessing and modifying an existing Date object.

Pros:

* May be faster than `new Date()`, especially if the input data can be reused
* Allows for caching of intermediate results

Cons:

* Requires an existing Date object, which may not always be available or cached
* Less straightforward and less readable code

### BASE (assigning a value to a variable)

This approach is unrelated to creating a new Date object. It simply assigns the input data (`nums[i]`) to a variable `d` without any further processing.

Pros:

* Simple and easy to understand
* No overhead of accessing internal functions or constructors

Cons:

* Not directly related to creating a new Date object, which may make it less efficient
* Less predictable performance compared to other approaches

**Library Considerations**

There is no explicit library mentioned in the benchmark, but `Date` objects are part of the JavaScript standard library. The `setTime()` method is also part of the same library.

**Special JS Features or Syntax**

The benchmark uses a modern feature called "template literals" (e.g., `nums[i] = now + i;`). This feature allows for more concise string interpolation and has been available in most modern JavaScript engines since ECMAScript 2015 (ES6).

Other alternatives to this benchmark could include:

* Measuring the performance of other Date-related methods, such as `getTime()`, `getMilliseconds()`, or `setMilliseconds()`.
* Comparing the performance of different libraries or frameworks that provide date-related functionality.
* Using more complex scenarios or edge cases to test the robustness and performance of each approach.

Keep in mind that the optimal approach will depend on specific use cases, requirements, and constraints. This benchmark provides a good starting point for understanding the relative performance of these three options, but further analysis and testing may be necessary to determine the best solution for a particular problem.

Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36

Browser/OS: Chrome 118 on Windows

View result in a separate tab

Test name	Executions per second
new Date()	4264.9 Ops/sec
setTime()	0.0 Ops/sec
BASE	15527.0 Ops/sec

Related benchmarks:

new-date-vs-date-settime (version: 0)

Comparing performance of: new Date() vs setTime() vs BASE

Created: 5 years ago by: Guest

Jump to the latest result

new Date()

setTime()

BASE

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):