Benchmark: Array slice, splice and direct access

Script Preparation code:

arr = [...Array(1000).keys()];
inds = [...Array(250).keys()];

Tests:

Slice
res = inds.map(i => arr.slice(i*4, (i+1) *4));
Splice
res = [] for (const i of inds) { res.push(arr.splice(0,4)); }
Direct
res = inds.map(i => [arr[i*4], arr[(i*4)+1], arr[(i*4)+2], arr[(i*4)+3]]);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Slice
Splice
Direct

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases to explain what's being tested, the options compared, pros and cons of each approach, and other considerations.

**Benchmark Definition and Test Cases**

The benchmark is designed to measure the performance of three different approaches for accessing elements in an array:

1. **Slice**: `arr.slice(i*4, (i+1) *4)`
2. **Splice**: `arr.splice(0,4)`
3. **Direct**: `[arr[i*4], arr[(i*4)+1], arr[(i*4)+2], arr[(i*4)+3]]`

The test cases create two arrays: `arr` with 1000 elements and `inds` with 250 elements. The arrays are then used to perform the three different access methods.

**Options Compared**

Each approach has its own strengths and weaknesses:

1. **Slice**: This method creates a new array containing a subset of elements from `arr`, starting at index `i*4` and ending at `(i+1) *4`. The advantage is that it's a simple and efficient way to access a range of elements.
	* Pros: Fast, easy to understand, and widely supported.
	* Cons: Creates a new array, which can be memory-intensive for large datasets.
2. **Splice**: This method modifies `arr` by removing the first 4 elements starting at index 0. The advantage is that it modifies the original data in place.
	* Pros: Modifies original data, potentially more efficient than creating a new array.
	* Cons: Can be slower due to the overhead of modifying an array, and can also cause unexpected behavior if not used carefully.
3. **Direct**: This method accesses individual elements of `arr` using direct indexing.
	* Pros: Can be faster for small datasets, as it avoids the overhead of creating a new array or modifying the original data.
	* Cons: Requires manual handling of indices, which can lead to errors.

**Library and Special JS Features**

There are no libraries used in this benchmark. However, it's worth noting that `Array.prototype.slice()` and `Array.prototype.splice()` are both part of the ECMAScript standard and are supported by most modern browsers.

No special JavaScript features are mentioned or required for this benchmark.

**Other Considerations**

* **Memory Usage**: The benchmark creates a new array with 1000 elements, which can consume significant memory.
* **Browser Behavior**: The behavior of the browser may vary depending on the specific implementation and version. For example, some browsers may use different algorithms for caching or memoization that could affect performance.

**Alternatives**

If you're interested in exploring alternative approaches or optimizations, consider the following:

1. **Using `Array.from()` instead of `Array.prototype.slice()```**: This can be a more efficient way to create an array from an existing iterable.
2. **Using `Array.prototype.subarray()` instead of `Array.prototype.slice()`**: This method is similar to `slice()`, but it returns an actual subarray object, which may be more suitable for certain use cases.
3. **Considering the use case and data distribution**: Depending on the specific requirements and characteristics of your dataset, other approaches or optimizations might be more suitable.

Keep in mind that this benchmark is designed to measure performance differences between three specific approaches, so exploring alternative methods would require a different set of benchmarks and test cases.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser/OS: Firefox 115 on Ubuntu

View result in a separate tab

Test name	Executions per second
Slice	69173.6 Ops/sec
Splice	41911.1 Ops/sec
Direct	81402.0 Ops/sec

Related benchmarks:

Array slice, splice and direct access (version: 0)

Comparing performance of: Slice vs Splice vs Direct

Created: one year ago by: Guest

Jump to the latest result

Slice

Splice

Direct

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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