Benchmark: Move an array element

HTML Preparation code:

<div id='1'></div>

Script Preparation code:

var arr = [1,2,3,4];

Tests:

splice
function arrayMove(arr, oldIndex, newIndex) { const copiedArr = [...arr]; const length = copiedArr.length; if (oldIndex !== newIndex && length > oldIndex && length > newIndex) { copiedArr.splice(newIndex, 0, copiedArr.splice(oldIndex, 1)[0]); } return copiedArr; } arrayMove(arr, 0, 3)
flatMap
function arrayMove(arr, oldIndex, newIndex) { const length = arr.length; const itemToMove = arr[oldIndex] if (oldIndex === newIndex || oldIndex > length || newIndex > length) { return arr; } return arr.flatMap((item, index) => { if (index === oldIndex) return []; if (index === newIndex) return oldIndex < newIndex ? [item, itemToMove] : [itemToMove, item]; return item; }) } arrayMove(arr, 0, 3)
reduce
function arrayMove(arr, oldIndex, newIndex) { const length = arr.length; const itemToMove = arr[oldIndex] if (oldIndex === newIndex || oldIndex > length || newIndex > length) { return arr; } return arr.reduce((acc, item, index) => { if (index === oldIndex) return acc; if (index === newIndex) return oldIndex < newIndex ? [...acc, item, itemToMove] : [...acc, itemToMove, item]; return [...acc, item]; }, []) } arrayMove(arr, 0, 3)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splice
flatMap
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Windows

View result in a separate tab

Test name	Executions per second
splice	8027132.5 Ops/sec
flatMap	5230823.5 Ops/sec
reduce	7343710.0 Ops/sec

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 analyze what's being tested.

**Benchmark Definition**

The benchmark defines three test cases: `splice`, `flatMap`, and `reduce`. Each test case has a similar structure:

1. A JavaScript function is defined to move an element from one index to another in an array.
2. The function takes two parameters: the original array, the old index of the element to be moved, and the new index where the element should be inserted.

**Options Compared**

The benchmark compares three different approaches for moving an element in an array:

1. **Splice**: Uses `arr.splice(newIndex, 0, arr[oldIndex])` to insert the element at the new index.
2. **flatMap**: Uses `arr.flatMap((item, index) => {...})` to create a new array with the element moved.
3. **Reduce**: Uses `arr.reduce((acc, item, index) => {...})` to accumulate the elements of the original array and insert the moved element at the correct position.

**Pros and Cons**

Here's a brief summary of each approach:

* **Splice**:
	+ Pros: Simple and efficient for small arrays.
	+ Cons: May not be suitable for large arrays due to its overhead in searching and inserting elements.
* **flatMap**:
	+ Pros: Can handle large arrays efficiently, as it avoids the need to search for the element.
	+ Cons: Creates a new array, which may lead to memory allocation issues for very large datasets.
* **Reduce**:
	+ Pros: Handles large arrays well and can be more efficient than `splice` for small to medium-sized arrays.
	+ Cons: Requires an accumulator variable, which can be slower than the other two approaches.

**Library**

There is no explicit library mentioned in the benchmark definition. However, `flatMap` is a method of the `Array.prototype` object in JavaScript, so it doesn't require any external libraries.

**Special JS Feature or Syntax**

None of the test cases use any special JavaScript features or syntax beyond standard ECMAScript 2022.

Related benchmarks:

Move an array element (version: 0)

Move an array element

Comparing performance of: splice vs flatMap vs reduce

Created: 3 years ago by: Guest

Jump to the latest result

splice

flatMap

reduce

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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