Benchmark: Slice vs splice first three elements

Script Preparation code:

var array = Array.from(Array(1000).keys());

Tests:

Slice
array.slice(0, 3);
Splice
array.splice(3)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Slice
Splice

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's tested in this specific benchmark.

**What is being tested?**

The provided JSON represents a JavaScript benchmark that measures the performance of two approaches to pick the first three elements from a large array: `array.slice(0, 3)` (Slice) and `array.splice(3)` (Splice).

In essence, the test cases aim to compare the execution time and efficiency of these two methods for achieving this specific task.

**Options compared**

There are two primary options being compared:

1. **`array.slice(0, 3)`**: This method creates a new array containing the first three elements of the original array. It does not modify the original array.
2. **`array.splice(3)`**: This method modifies the original array by removing and returning the first three elements.

**Pros and Cons**

*   **Slice**
    *   Pros:
        *   Does not modify the original array, making it suitable for large datasets where preserving the original data is crucial.
        *   Creates a new array with the desired elements, which can be more efficient in terms of memory usage compared to modifying the original array.
    *   Cons:
        *   Requires creating a new array, which may incur additional memory allocation and copying costs.
*   **Splice**
    *   Pros:
        *   Modifies the original array in-place, reducing memory allocation and copying overhead.
        *   Can be faster for smaller arrays since it only needs to shift elements instead of allocating new space.
    *   Cons:
        *   Modifies the original array, which may have unintended consequences (e.g., losing data).
        *   Can be slower for large datasets due to the overhead of modifying the array.

**Library and purpose**

There is no specific library mentioned in the benchmark definition. However, the use of `Array.from()` and `Array.keys()` suggests that the test is using a modern JavaScript environment with access to these methods.

**Special JS feature or syntax**

The benchmark does not explicitly mention any special JavaScript features or syntax. It relies on standard ECMAScript features, making it accessible to most JavaScript developers without requiring specific knowledge of advanced features like async/await, destructuring, or classes.

**Alternatives**

If you're interested in exploring alternative approaches for picking the first three elements from an array, consider these options:

1.  **Using `Array.prototype.slice()` with negative indices**: Instead of using `slice(0, 3)`, you could use `slice(-3)` to achieve the same result.
2.  **Using a custom implementation**: Depending on your specific requirements, you might want to implement a custom solution using loops or other methods.

Keep in mind that these alternatives may have different performance characteristics and trade-offs compared to the Slice and Splice approaches tested in this benchmark.

In conclusion, this JavaScript microbenchmark provides a clear comparison of two common approaches for picking the first three elements from an array. Understanding the pros and cons of each method can help you choose the most suitable approach for your specific use case.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
Slice	5925455.0 Ops/sec
Splice	6093619.0 Ops/sec

Related benchmarks:

Slice vs splice first three elements (version: 0)

Picking the three first elements of a largeish array

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>

Experimental features:

Fastest: N/A

Slowest: N/A

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