Benchmark: Array slice() vs slice(0) vs spread operatorr

Script Preparation code:

var baseArray = []
for (var i = 0; i < 50; i++) {
  baseArray.push((Math.floor(Math.random() * Math.floor(1000000))).toString(16)) 
}

Tests:

Array.prototype.slice()
var other = baseArray.slice();
spread operator
var other = null;
Array.prototype.slice(0)
var other = baseArray.slice(0);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.slice()
spread operator
Array.prototype.slice(0)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its results.

**Benchmark Definition**

The benchmark compares three different approaches for creating a new array from an existing one:

1. **Traditional `slice()` method**: This approach uses the `Array.prototype.slice()` method, which returns a shallow copy of a portion of an array.
2. **Spread operator (`...`)**: This approach uses the new ES6 spread operator, which creates a new array by spreading the elements of an existing array.

**Options being compared**

The benchmark is comparing the performance of these two approaches:

* `Array.prototype.slice()`
* Spread operator (`...`)

**Pros and cons of each approach**

1. **Traditional `slice()` method**:
	* Pros: widely supported, easy to understand, and well-documented.
	* Cons: can be slow for large arrays, as it creates a new array by copying elements.
2. **Spread operator (`...`)**:
	* Pros: modern and efficient way to create a new array, especially for smaller datasets.
	* Cons: not supported in older browsers, and its syntax might be unfamiliar to some developers.

**Library and special JS feature**

In this benchmark, the library used is none. However, it's worth noting that the spread operator was introduced in ECMAScript 2015 (ES6), which means it's a relatively new feature.

**Other considerations**

When comparing these two approaches, it's essential to consider the size of the dataset being processed. For smaller datasets, the spread operator might be faster due to its simplicity and lack of overhead. However, for larger datasets, the traditional `slice()` method might still be faster because it creates a new array by copying elements.

**Alternatives**

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

* Using `Array.prototype.slice()` with optional arguments (e.g., `slice(10)` to start from index 10).
* Using `Array.prototype.concat()` with an empty array or another array.
* Using a library like Lodash, which provides the `_.slice()` function.

In summary, this benchmark highlights the importance of considering performance and syntax when choosing an approach for creating a new array from an existing one.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:106.0) Gecko/20100101 Firefox/106.0

Browser/OS: Firefox 106 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Array.prototype.slice()	21479574.0 Ops/sec
spread operator	1577579520.0 Ops/sec
Array.prototype.slice(0)	21529638.0 Ops/sec

Related benchmarks:

Array slice() vs slice(0) vs spread operatorr (version: 0)

Compare the new ES6 spread operator with the traditional slice() methods

Comparing performance of: Array.prototype.slice() vs spread operator vs Array.prototype.slice(0)

Created: one year ago by: Guest

Jump to the latest result

Array.prototype.slice()

spread operator

Array.prototype.slice(0)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):