Benchmark: Array clone - MeasureThat.net

Script Preparation code:

var arr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];

Tests:

spread
const arr2 = [...arr];
slice
const arr3 = arr.slice(0);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
slice

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.1:latest, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the details of this benchmark.

**Benchmark Definition**

The benchmark is called "Array clone" and it involves cloning an array in JavaScript. The preparation code creates an array `arr` with 20 elements.

**Test Cases**

There are two test cases:

1. **Spread**: This test case uses the spread operator (`...`) to create a shallow copy of the original array.
2. **Slice**: This test case uses the `slice()` method to create a shallow copy of the original array.

**Library**

No external library is used in this benchmark.

**Special JS feature or syntax**

The spread operator (`...`) is a special feature introduced in ECMAScript 2015 (ES6). It allows you to expand an iterable (such as an array) into individual elements. In this case, it's used to create a new array by spreading the contents of the original array.

**Pros and Cons**

Here's a brief comparison of the two approaches:

* **Spread**: This approach is concise and easy to read. However, it can be slower than `slice()` for large arrays, as it involves creating a new array and iterating over each element.
* **Slice**: This approach creates a shallow copy of the original array by slicing it from index 0 to the end. It's generally faster than spread for large arrays, but may not work correctly if the original array contains mutable objects.

**Other Alternatives**

Here are some other ways to clone an array in JavaScript:

* **Concat**: You can use the `concat()` method to create a new array by concatenating the original array with an empty array. This approach is slower than spread and slice, but may be useful if you need to clone multiple arrays.
* **JSON.parse(JSON.stringify())**: This approach uses the JSON API to serialize and deserialize the array, which can be slow for large arrays.

Overall, this benchmark demonstrates a simple example of how to measure the performance differences between two common approaches to cloning an array in JavaScript.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0

Browser/OS: Firefox 60 on Windows 7

View result in a separate tab

Test name	Executions per second
spread	2095073.8 Ops/sec
slice	5598239.5 Ops/sec

Related benchmarks:

Array clone (version: 0)

Comparing performance of: spread vs slice

Created: 6 years ago by: Guest

Jump to the latest result

spread

slice

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.1:latest, generated 27 days ago):