Benchmark: slice VS splice : who get first 10 items faster

Script Preparation code:

var list1 = [];
var list2 = [];
for (var i = 0; i < 1000 * 1000; i++) {
    list1.push(i);
    list2.push(i);
}

Tests:

slice
list = list1.slice(0, 10);
splice
list2.splice(10, list.length - 10);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
splice

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark measures which method is faster: using `Array.prototype.slice()` or `Array.prototype.splice()`. The test is designed to compare these two methods on a large array of 100,000 elements.

**What are we testing?**

We're testing the execution time of both `slice` and `splice` methods when used to extract the first 10 elements from an array. The tests use identical preparation code to ensure that only the differences in the method implementation affect the results.

**Options compared:**

1. **Array.prototype.slice()**: This method returns a shallow copy of a portion of an array, starting at the specified start index and ending at the specified end index (exclusive). It creates a new array object containing the selected elements.
2. **Array.prototype.splice()**: This method modifies the original array by removing or replacing existing elements and/or adding new elements to the array. In this case, we're using it to extract the first 10 elements from the array.

**Pros and Cons:**

1. **slice()**:
	* Pros: Fast, efficient, and creates a new copy of the array, which can be beneficial when working with large arrays or in certain situations where modifying the original array is not desired.
	* Cons: Creates a new array object, which requires additional memory allocation and can lead to performance overhead due to garbage collection.
2. **splice()**:
	* Pros: Modifies the original array in-place, reducing memory allocation and deallocation overhead. It's also more concise and often preferred when removing or replacing elements within an array.
	* Cons: Slower than `slice()` since it requires modifying the original array, which can lead to performance penalties.

**Library and Purpose**

In this benchmark, there is no explicit library used beyond the built-in JavaScript Array prototype. However, if you were to use a third-party library that extends or modifies the array implementation, it could potentially affect the results.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax being tested in this benchmark. The focus is solely on comparing the performance of two standard method implementations within the Array prototype.

**Other Alternatives**

If you're interested in exploring alternative approaches for extracting elements from an array, consider:

1. **Using `Array.prototype.indexOf()` and `Array.prototype.slice()`**: This approach uses `indexOf()` to find the index of the first element matching a specified value and then uses `slice()` to extract that element.
2. **Using `Array.prototype.map()`**: Although not directly applicable for extracting elements, using `map()` can create a new array with transformed elements, similar to how `slice()` creates a copy.

Keep in mind that these alternatives may have different performance characteristics compared to the original methods being tested.

Related benchmarks:

slice VS splice : who get first 10 items faster (version: 0)

100k list splice and shift win, they mutate list slice loose, it creates a copy of list 7.5x slower

Comparing performance of: slice vs splice

Created: 3 years ago by: Guest

Jump to the latest result

slice

splice

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):