Benchmark: Remove element from array splice vs copyWithin

Script Preparation code:

var array1 = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99]
var array2 = array1.slice();

function deleteBySplice (array,index) {
  array.splice( index, 1 );
}

function deleteByCopyWithin (array, index) {
  array.copyWithin( index, index + 1 );
  array.pop();
}

Tests:

deleteBySplice
for (let i = array1.length; i >= 0; i-=3) { deleteBySplice(array1, i); }
deleteByCopyWithin
for (let i = array2.length; i >= 0; i-=3) { deleteByCopyWithin(array2, i); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
deleteBySplice
deleteByCopyWithin

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 benchmark and explain what's being tested.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmarking test case. It defines two functions, `deleteBySplice` and `deleteByCopyWithin`, which are designed to remove an element from an array using different approaches.

**What is tested?**

In this test, we're comparing the performance of two ways to remove an element from an array:

1. **Using `splice()`**: The `deleteBySplice` function removes the element at a specified index from the array by calling `array.splice(index, 1)`.
2. **Using `copyWithin()` and then `pop()`**: The `deleteByCopyWithin` function achieves similar result by copying elements from an offset within the array to a new position, effectively shifting all elements after that offset one position forward, and then removing the last element using `array.pop()`.

**Options compared**

The two approaches have different time complexities:

* `splice()`: O(n), where n is the number of elements in the array being modified. This is because `splice()` needs to shift all elements after the insertion point.
* `copyWithin()` and then `pop()` : O(n) amortized, but can be faster in practice for large arrays due to the way it uses a contiguous block of memory.

**Pros and Cons**

**`splice()`:**

Pros:

* Simpler implementation
* Generally faster for small to medium-sized arrays

Cons:

* Slower for large arrays due to shifting all elements after the insertion point

**`copyWithin()` and then `pop()` :**

Pros:

* Can be faster for large arrays, as it uses a contiguous block of memory
* More efficient than `splice()` when removing multiple elements from an array

Cons:

* More complex implementation
* Can be slower for small arrays due to the overhead of copying data

**Library and special features used**

In this benchmark, no specific JavaScript library is used. However, both functions use standard JavaScript APIs.

There are no special JS features or syntax explicitly mentioned in this test case.

Related benchmarks:

Remove element from array splice vs copyWithin (version: 0)

Comparing performance of: deleteBySplice vs deleteByCopyWithin

Created: 3 years ago by: Guest

Jump to the latest result

deleteBySplice

deleteByCopyWithin

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):