Benchmark: Array: Slice vs Spread perf

Tests:

slice
const data = Array.from({ length: 1e6 }, () => Math.random()) const result = data.slice(2)
spread
const data = Array.from({ length: 1e6 }, () => Math.random()) const [,,result] = data

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.72 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
slice	4.2 Ops/sec
spread	4.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, along with the pros and cons of each approach.

**Benchmark Overview**

The MeasureThat.net benchmark compares the performance of two ways to create an array slice: using `Array.prototype.slice()` (the traditional method) and using the spread operator (`...`) to extract a subset of elements from the array. The benchmark measures the execution time of both approaches for creating an array with 1 million random elements, slicing off the first three elements.

**Options Compared**

The two options being compared are:

1. **`Array.prototype.slice()`**: This is the traditional method for creating an array slice. It takes a start and end index as arguments and returns a new array containing the elements between those indices.
2. **Spread Operator (`...`)**: This method uses the spread operator to extract a subset of elements from the array. It's a more modern and concise way of creating arrays, but it can be slower than the traditional `slice()` method.

**Pros and Cons**

1. **`Array.prototype.slice()`**:
	* Pros:
		+ Faster execution time
		+ Widely supported and well-understood method
	* Cons:
		+ Can be verbose (e.g., `data.slice(2)` instead of `[,,result]`)
2. **Spread Operator (`...`)**:
	* Pros:
		+ More concise and readable code
		+ Less verbose than traditional slicing methods
	* Cons:
		+ Can be slower execution time due to the overhead of creating a new array

**Library Used**

In this benchmark, the `Array.from()` method is used to create an array with random elements. This method is a modern way of creating arrays in JavaScript and is supported by most browsers.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark.

**Other Considerations**

* The benchmark assumes that the input data is large (1 million elements) to demonstrate the performance difference between the two methods.
* The benchmark runs on a desktop platform with Chrome 90, which may not be representative of all environments.

**Alternatives**

If you want to create an array slice in JavaScript, there are other options besides `Array.prototype.slice()` and the spread operator. Some alternatives include:

1. **`Array.prototype.concat()`**: You can use `concat()` method to concatenate two arrays, but this is generally slower than using `slice()` or the spread operator.
2. **`Array.prototype.splice()`**: Splice() method can be used to remove elements from an array, but it's not designed for creating a slice.

Overall, the benchmark highlights the trade-off between conciseness and performance in JavaScript array operations. The traditional `Array.prototype.slice()` method is generally faster, but the spread operator provides a more modern and readable way of creating arrays.

Related benchmarks:

Array: Slice vs Spread perf (version: 0)

Comparing performance of: slice vs spread

Created: 3 years ago by: Guest

Jump to the latest result

slice

spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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