Benchmark: slice VS splice VS shift for removing multiple items

Script Preparation code:

var list = [];
for (var i = 0; i < 10000; i++) {
  list.push(i);
}

Tests:

slice
list = list.slice(100);
splice
list.splice(0, 100);
shift
n = 100; while (n-- > 0) list.shift();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
splice
shift

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into the provided Benchmark Definition JSON and explain what's being tested, the options compared, their pros and cons, and other considerations.

**Benchmark Overview**

The benchmark tests three different approaches for removing multiple items from an array: `slice()`, `splice()`, and `shift()`. The test creates a large array with 10,000 elements and then removes 100 elements using each approach. The goal is to determine which approach is the fastest.

**Options Compared**

1. **`slice()`**: This method returns a shallow copy of a portion of an array. In this case, it removes the first 100 elements from the array.
2. **`splice()`**: This method modifies the original array by removing or inserting elements at a specified position. Here, it removes the first 100 elements from the array.
3. **`shift()`**: This method removes the first element from an array and returns it.

**Pros and Cons**

* `slice()`:
	+ Pros: Efficient for large arrays since it only creates a new array object without modifying the original.
	+ Cons: May incur a higher overhead due to the creation of a new array object.
* `splice()`: 
	+ Pros: Modifies the original array, potentially reducing memory allocation and deallocation.
	+ Cons: Can be slower for large arrays since it requires shifting elements to fill the gap.
* `shift()`:
	+ Pros: Fastest approach since it only involves removing an element from the beginning of the array without creating new objects or modifying the original.
	+ Cons: Only suitable for small arrays, as it will shift all subsequent elements.

**Library and Special JS Features**

None of the benchmarked functions use any external libraries. However, `shift()` does utilize a built-in JavaScript feature that allows it to remove an element from the beginning of the array without creating new objects or modifying the original.

**Other Considerations**

* Performance: The order in which elements are removed can affect performance. In this case, removing from the end (`shift()`) is likely to be faster than removing from the beginning (`slice()`).
* Memory allocation and deallocation: `splice()` may incur more memory allocation and deallocation compared to `slice()`, as it modifies the original array.
* Syntax complexity: While all three functions are relatively simple, `splice()` can be more complex due to its ability to insert or remove elements at arbitrary positions.

**Alternatives**

If you were to implement a different approach for removing multiple items from an array, some alternatives could include:

1. Using `filter()`: Create a new array with only the desired elements.
2. Using `map()` and `concat()`: Convert each element to a new array and concatenate them together.
3. Using a loop: Iterate through the array and remove elements individually.

However, these approaches may not be as efficient or scalable as the benchmarked methods.

Related benchmarks:

slice VS splice VS shift for removing multiple items (version: 0)

Comparing performance of: slice vs splice vs shift

Created: 4 years ago by: Guest

Jump to the latest result

slice

splice

shift

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):