Benchmark: slice vs array from

HTML Preparation code:

<div></div><div></div><div></div><div></div><div></div><div></div><div></div>

Script Preparation code:

window.elements = document.querySelectorAll("div");

Tests:

slice
[].slice.call(window.elements);
array from
Array.from(window.elements);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
array from

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser/OS: Chrome 124 on Windows

View result in a separate tab

Test name	Executions per second
slice	488986.9 Ops/sec
array from	371976.2 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the provided benchmark.

**Benchmark Overview**

The MeasureThat.net benchmark is designed to compare the performance of two approaches: using the `slice()` method and using `Array.from()`. The benchmark creates an array of HTML elements, which are generated by querying the `window` object. The test cases measure how long it takes for each approach to execute.

**Benchmark Definition JSON**

The Benchmark Definition JSON provides a basic structure for defining the benchmark. It contains:

* `Name`: A unique identifier for the benchmark.
* `Description`: An optional description of the benchmark (not used in this case).
* `Script Preparation Code`: JavaScript code that is executed before running the benchmark. In this case, it sets up an array of HTML elements using `window.elements = document.querySelectorAll("div")`.
* `Html Preparation Code`: HTML code that is generated to create a set of HTML elements for testing. This is used to ensure consistent test results.

**Individual Test Cases**

The two test cases are:

1. **"slice"`**: Measures the time it takes to execute `[].slice.call(window.elements);`.
2. **"array from"`**: Measures the time it takes to execute `Array.from(window.elements);`.

**Options Compared**

In this benchmark, we have two options being compared:

* Using `slice()` method
* Using `Array.from()`

Both methods are used to create a new array from the existing elements.

**Pros and Cons of Each Approach**

1. **Using `slice()` method**:
	* Pros:
		+ More efficient, as it uses a native JavaScript function.
		+ Less memory-intensive, since it only creates a reference to the original array.
	* Cons:
		+ May not be supported in older browsers or versions of JavaScript.
2. **Using `Array.from()` method**:
	* Pros:
		+ More modern and widely supported, as it is part of the ECMAScript standard.
		+ Can handle arrays of arbitrary types, including strings and dates.
	* Cons:
		+ May be slower than `slice()`, due to additional overhead.

**Library Used**

In this benchmark, no external libraries are used. However, the `window` object is assumed to provide access to the HTML document's elements.

**Special JS Feature or Syntax**

There is no special JavaScript feature or syntax used in this benchmark. The code only uses native JavaScript functions and methods.

**Other Alternatives**

Other alternatives for creating a new array from an existing array include:

* `Array.prototype.slice.call()`: This method is similar to the `slice()` function, but it's called on the `Array` prototype.
* `Array.from()` with an iterable: In addition to using `window.elements`, you could also use other iterables, such as an `ArrayBuffer` or a `DataView`.
* Manual iteration using `for...of`: You could create a new array by iterating over the original array using a `for...of` loop.

Note that the choice of alternative will depend on the specific requirements and constraints of your project.

Related benchmarks:

slice vs array from (version: 0)

Comparing performance of: slice vs array from

Created: one year ago by: Guest

Jump to the latest result

slice

array from

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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