Benchmark: Slice vs Splice vs Shift vs Spread syntax

Script Preparation code:

var array = [1, 2, 3, 4, 5, 6, 7, 8]
var itemsToRemove = 2

Tests:

array.slice()
array = array.slice(2)
array.splice()
array.splice(0, itemsToRemove)
array.shift()
for (let i = 0 ; i < itemsToRemove ; i++) array.shift()
Spread syntax
var [one, tow, ...others] = array; array = others;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.slice()
array.splice()
array.shift()
Spread syntax

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net. The benchmark is designed to compare the speed of four different approaches for removing 2 items from the beginning of an array:

1. `array.slice(2)`
2. `array.splice(0, 2)`
3. `for (let i = 0; i < 2; i++) array.shift()`
4. Spread syntax (`var [one, tow, ...others] = array; array = others;`)

Each test case defines a separate benchmarking scenario, with the script preparation code and HTML preparation code specified.

**Comparison of Approaches**

Here's an overview of each approach, their pros and cons:

1. **`array.slice(2)`**: This method creates a new array by slicing the original array from index 2 to the end. It's a simple and efficient way to remove elements.
	* Pros: Fast, easy to implement, and doesn't modify the original array.
	* Cons: Creates a new array, which can be memory-intensive for large datasets.
2. **`array.splice(0, 2)`**: This method modifies the original array by removing the first two elements. It's a more efficient way to remove elements compared to slicing.
	* Pros: Fast, modifies the original array, and doesn't create a new one.
	* Cons: Modifies the original array, which might be undesirable in some cases.
3. **`for (let i = 0; i < 2; i++) array.shift()`**: This method uses a loop to shift each element from the beginning of the array until two elements are removed.
	* Pros: Easy to understand and implement, doesn't modify the original array.
	* Cons: Slow compared to other methods (O(n) complexity), creates multiple temporary variables.
4. **Spread syntax (`var [one, tow, ...others] = array; array = others;`)**: This method uses the spread operator to create a new array by extracting elements from the original array.
	* Pros: Fast, easy to implement, and doesn't modify the original array.
	* Cons: Might be slower than other methods for very large datasets due to the overhead of creating a new array.

**Library and Special Features**

The test case does not explicitly use any libraries or special features like async/await, Promises, or Web Workers. However, it's worth noting that MeasureThat.net might be using some internal library or mechanism to execute the benchmarks.

**Other Considerations**

* The benchmark measures the number of executions per second (ExecutionsPerSecond) for each test case.
* The test cases are executed on a desktop environment with Chrome 125 and Windows operating system.
* The raw UA string is included in the benchmark result, which might indicate specific browser or device characteristics.

**Alternatives**

Some alternative approaches to removing elements from an array could include:

* Using `Array.prototype.forEach()` with the `continue` statement to skip over elements
* Utilizing `Map` data structure instead of arrays for efficient lookups and removals
* Implementing custom iteration mechanisms, like using `IndexedCollection` or `ArrayView`

However, these alternatives might not be as straightforward or well-supported as the methods compared in the benchmark.

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Windows

View result in a separate tab

Test name	Executions per second
array.slice()	10141853.0 Ops/sec
array.splice()	12222229.0 Ops/sec
array.shift()	5769088.0 Ops/sec
Spread syntax	11104022.0 Ops/sec

Related benchmarks:

Slice vs Splice vs Shift vs Spread syntax (version: 0)

Compares the speed for removing 2 items from the beginning of an array

Comparing performance of: array.slice() vs array.splice() vs array.shift() vs Spread syntax

Created: 5 months ago by: Registered User

Jump to the latest result

array.slice()

array.splice()

array.shift()

Spread syntax

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):