Benchmark: Array.prototype.slice vs spread operator with length limit

Script Preparation code:

var limit = 1000
var a = new Array(limit).fill(limit);

Tests:

Array.prototype.slice
var b = a.slice(); b.unshift(limit);
spread operator
var b = [ limit, ...a ];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.slice
spread operator

Fastest: N/A

Slowest: N/A

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

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Let's break down the benchmark test case.

**What is being tested?**

The benchmark is comparing two approaches to create a new array by copying an existing array:

1. `Array.prototype.slice()`
2. The ES6 spread operator (`...`)

**Options compared:**

The two options are compared in terms of performance, which is the primary metric being measured.

**Pros and Cons of each approach:**

1. **`Array.prototype.slice()`**:
	* Pros:
		+ Widely supported across different browsers and versions.
		+ Efficient for small to medium-sized arrays.
	* Cons:
		+ Creates a new array object, which can lead to performance issues with very large arrays.
2. **ES6 spread operator (`...`)**:
	* Pros:
		+ More efficient than `slice()` for large arrays, as it only creates a single array object.
		+ Less memory-intensive.
	* Cons:
		+ Requires support for the ES6 syntax and modern browsers.

**Library/Utility:**

There is no specific library or utility being used in this benchmark. The focus is solely on comparing the two JavaScript operators.

**Special JS feature/syntax:**

The ES6 spread operator (`...`) is a new syntax introduced in ECMAScript 2015 (ES6). It allows for creating a new array by copying elements from an existing array, without the need for `Array.prototype.slice()` or other methods.

**Other alternatives:**

If you wanted to use alternative approaches to create a new array, some options could be:

* Using `Array.prototype.concat()`: This method creates a new array by concatenating multiple arrays. However, it may not be as efficient as `slice()` for very large arrays.
* Using `Array.from()`: This method creates a new array from an iterable or an array-like object. It may be more suitable than `slice()` for creating arrays with specific elements.

In general, when working with arrays in JavaScript, the choice of approach depends on the specific use case and performance requirements.

Keep in mind that this benchmark is focused on comparing two specific approaches within the JavaScript language, rather than exploring alternative programming paradigms or languages.

Related benchmarks:

Array.prototype.slice vs spread operator with length limit (version: 0)

Compare the ES6 spread operator with the traditional slice() method

Comparing performance of: Array.prototype.slice vs spread operator

Created: 5 years ago by: Guest

Jump to the latest result

Array.prototype.slice

spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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