Benchmark: slice vs new array

Script Preparation code:

var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Tests:

slice all
var brr = arr.slice()
slice half
var crr = arr.slice(4,6)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice all
slice half

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript microbenchmark on MeasureThat.net.

**Benchmark Definition**

The benchmark is designed to compare two approaches for creating an array from the `arr` variable: using the `slice()` method versus creating a new array using the `new Array()` constructor.

**Options Compared**

There are only two options being compared:

1. **Slice Method**: `var brr = arr.slice()`
2. **New Array Constructor**: `var crr = new Array(arr.length)`

**Pros and Cons of Each Approach**

* **Slice Method**:
	+ Pros: Efficient, creates a shallow copy of the original array, easy to use.
	+ Cons: Can be slower for large arrays due to the overhead of creating a new object.
* **New Array Constructor**:
	+ Pros: Allows for more control over array creation (e.g., specifying initial values), can be faster for very large arrays.
	+ Cons: Requires explicit knowledge of the array length, can be less intuitive.

**Library Used**

None is explicitly mentioned. The `slice()` method is a built-in JavaScript function that creates a shallow copy of an array.

**Special JS Feature or Syntax**

The benchmark uses the spread operator (`...`) in the HTML preparation code, which is not relevant to the comparison being made. However, it's worth noting that the spread operator is available in modern JavaScript versions (ECMAScript 2018+).

**Other Alternatives**

If you wanted to add more alternatives, you could consider including:

* Using `Array.prototype.slice.call()` or `Array.prototype.slice.apply()`
* Creating an array using `Object.create()` and then setting its elements
* Using a library like Lodash's `slice` function

Here are some brief explanations for these additional alternatives:

* **`Array.prototype.slice.call()` or `Array.prototype.slice.apply()`**: These methods apply the slice method to an existing array-like object. They provide more control over the resulting array but may not be as efficient.
* **`Object.create()` and then setting its elements**: This approach creates a new object using `Object.create()`, then sets its properties using `arr.forEach((element, index) => crr[index] = element);`. While it can create an array-like object, it's more verbose and less efficient than the other options.
* **Lodash's `slice` function**: This library provides a highly optimized slice function that is faster than the built-in method. However, it requires including an external library.

Keep in mind that these alternative approaches may not be relevant to the specific use case of creating an array from a given array variable, but they demonstrate additional ways to approach the problem.

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/119.0

Browser/OS: Firefox 119 on Ubuntu

View result in a separate tab

Test name	Executions per second
slice all	36119840.0 Ops/sec
slice half	48492080.0 Ops/sec

Related benchmarks:

slice vs new array (version: 0)

Comparing performance of: slice all vs slice half

Created: 10 months ago by: Registered User

Jump to the latest result

slice all

slice half

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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