Benchmark: Slice vs Splice vs Shift for 1 item

Script Preparation code:

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

Tests:

array.slice()
array = array.slice(1)
array.splice()
array.splice(0, itemsToRemove)
array.shift()
array.shift()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

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/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
array.slice()	5727531.0 Ops/sec
array.splice()	30240254.0 Ops/sec
array.shift()	54843328.0 Ops/sec

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the details of this benchmark.

**What is being tested?**

The test compares three different methods for removing one item from the beginning of an array in JavaScript:

1. `array.slice(1)`
2. `array.splice(0, itemsToRemove)`
3. `array.shift()`

These methods are all used to remove one or more elements from the start of an array.

**What options are compared?**

The test compares three different approaches to removing one item from the beginning of an array:

* `slice()`: Creates a new array by copying all elements except the first one.
* `splice()`: Modifies the original array by removing elements at specific indices (in this case, the first element).
* `shift()`: Removes and returns the first element of the original array.

**Pros/Cons of each approach:**

1. **`slice()`**: Pros:
	* Creates a new array without modifying the original.
	* Can be used to create a copy of an array for further processing.
	* Cons:
		+ More expensive in terms of CPU cycles, as it creates a new array.
2. **`splice()`**: Pros:
	* Modifies the original array, which can be beneficial when working with large datasets.
	* Can be used to remove elements at specific indices (not just the first element).
	* Cons:
		+ May cause unnecessary reallocations or copying of data if not used carefully.
3. **`shift()`**: Pros:
	* Removes and returns the first element, making it suitable for scenarios where you need to process the removed item separately.
	* Modifies the original array, which can be beneficial when working with large datasets.
	* Cons:
		+ May cause unnecessary reallocations or copying of data if not used carefully.

**What library is being used?**

No external libraries are being used in this test. The JavaScript standard library and built-in methods are sufficient for these operations.

**What special JS feature or syntax is being used?**

None specific to the benchmark itself. However, `splice()` is a method that requires an understanding of array indices and modifications, which might not be immediately familiar to all developers.

**Other alternatives:**

For removing one item from the beginning of an array, you could also consider using a simple assignment operation:

```javascript
array[0] = null;
```

However, this approach does not return the removed element and modifies the original array without creating a new copy. It's generally less efficient than the three methods being compared.

Another option would be to use `pop()` method in conjunction with `unshift()`, but it's not the most straightforward or efficient solution:

```javascript
array.pop();
array.unshift(); // This will reset the array, effectively removing the first element.
```

Keep in mind that these alternatives might have different implications depending on your specific use case and requirements.

Related benchmarks:

Slice vs Splice vs Shift for 1 item (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()

Created: 2 years ago by: Guest

Jump to the latest result

array.slice()

array.splice()

array.shift()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):