Benchmark: array spread vs splice.apply

Script Preparation code:

var arr1 = new Array(10);
var arr2 = new Array(10);
var arr3 = new Array(10);
var arr4 = new Array(10);
var arr5 = new Array(10);
var arr6 = new Array(10);
var arr7 = new Array(10);
var arr8 = new Array(10);
arr1.fill(1);
arr2.fill(2);
arr3.fill(1);
arr4.fill(2);
arr5.fill(1);
arr6.fill(2);
arr7.fill(1);
arr8.fill(2);

Tests:

array spread
var result = [...arr1, ...arr2]
splice.apply
Array.prototype.splice.apply(arr3, [arr4.length, 0].concat(arr4))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array spread
splice.apply

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark measures the performance difference between two approaches to achieve a similar result:

1. Using the spread operator (`...`) to create a new array with elements from `arr1` and `arr2`.
2. Using the `splice.apply()` method to modify `arr3` by replacing its contents with elements from `arr4`.

**Approaches Compared**

The two approaches being compared are:

1. **Array Spread**: Creating a new array using the spread operator (`...`) to combine `arr1` and `arr2`. This creates a new array object and copies the elements from `arr1` and `arr2` into it.
2. **splice.apply()**: Using the `splice.apply()` method to modify `arr3` by replacing its contents with elements from `arr4`. The `apply()` method applies the `splice()` method on the array, allowing us to specify the index (in this case, 0) and number of elements (the length of `arr4`) to insert.

**Pros and Cons**

Here are some pros and cons of each approach:

**Array Spread:**

Pros:

* Creates a new array object, avoiding modifying the original arrays.
* Can be more readable and easier to understand for some developers.

Cons:

* May incur additional overhead due to creating a new array object.
* May not perform as well if the resulting array is very large.

**splice.apply():**

Pros:

* Avoids creating a new array object, potentially reducing overhead.
* Can be faster if the modified array is relatively small.

Cons:

* Modifies the original arrays (`arr1` and `arr2`) when using the spread operator.
* May have a steeper learning curve for some developers.

**Other Considerations**

Both approaches assume that the resulting array should be ordered in the same way as the original arrays. If this assumption is not valid, additional logic may be required to sort or reorder the elements.

**Library and JavaScript Feature**

The `fill()` method used to initialize the array elements (`arr1.fill(1)` and `arr2.fill(2)`) is a built-in JavaScript method that fills an array with a specified value. This method was introduced in ECMAScript 5 (ES5).

No special JavaScript features or syntax are being tested in this benchmark.

**Alternatives**

Other alternatives for creating new arrays or modifying existing ones include:

* `concat()`: A built-in method that concatenates two or more arrays into a single array.
* `slice()`: A built-in method that creates a shallow copy of a portion of an array.
* Using `map()` and `reduce()` methods to create a new array from an existing one.

These alternatives may have different performance characteristics depending on the specific use case and requirements.

Related benchmarks:

array spread vs splice.apply (version: 0)

Comparing performance of: array spread vs splice.apply

Created: 5 years ago by: Guest

Jump to the latest result

array spread

splice.apply

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):