Benchmark: Splice vs Spread (immutable only)

Tests:

Splice method
const arr = [0,1,2,3,4,5,6,7,8,9]; let out = [...arr].splice(2, 1, 123)
Spread method
const arr = [0,1,2,3,4,5,6,7,8,9]; let out = [...arr.slice(0,2), 123, ...arr.slice(3)];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Splice method
Spread method

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:147.0) Gecko/20100101 Firefox/147.0

Browser/OS: Firefox 147 on Windows

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Test name	Executions per second
Splice method	5668092.5 Ops/sec
Spread method	4715451.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview**

The provided JSON represents two microbenchmarks for testing the performance of JavaScript's array methods, specifically `splice` and `spread`. The benchmarks aim to compare the execution speed of these methods when used with immutable arrays.

**Benchmark Definition**

The benchmark definition specifies that:

* An initial array `arr` is created with 10 elements.
* The `splice` method is used to remove the middle element (index 2) and insert a new value (123).
* The `spread` method is used to create a new array by spreading the first two elements of `arr`, inserting 123, and then spreading the remaining elements.

**Options Compared**

The two options being compared are:

1. **Splice Method**: This method modifies the original array in place, removing the element at index 2 and replacing it with 123.
2. **Spread Method**: This method creates a new array by spreading the first two elements of `arr`, inserting 123, and then spreading the remaining elements.

**Pros and Cons**

* **Splice Method**:
	+ Pros: Can be faster for small arrays or when only modifying the middle element.
	+ Cons: Modifies the original array, which can lead to unexpected behavior in certain contexts.
* **Spread Method**:
	+ Pros: Creates a new array without modifying the original, which can be safer and more predictable.
	+ Cons: May be slower due to the overhead of creating a new array.

**Library**

In both benchmark cases, no libraries are explicitly mentioned. However, `slice()` is used in one of the test cases, which is a built-in JavaScript method for creating a shallow copy of an array.

**Special JS Feature/Syntax**

Neither of the benchmarks uses any special JavaScript features or syntax beyond what is commonly available in modern browsers. They only utilize standard JavaScript methods and arrays.

**Other Alternatives**

For similar benchmarking purposes, you can consider using other approaches:

1. **Array destructuring**: Instead of using `splice()` or `slice()`, you could use array destructuring to extract elements from the original array.
2. **Concats**: Use the `concat()` method instead of `spread()` to combine arrays.
3. **Iterators**: Use iterators to iterate over the array elements, which can be useful for certain optimization scenarios.

Keep in mind that these alternatives may not provide the same level of performance comparison as the original `splice` and `spread` methods, but they can still help you explore different approaches to optimizing your code.

In summary, the benchmark is designed to compare the performance of two array methods (`splice()` and `spread()`) when used with immutable arrays. The results will show which method is faster, while taking into account any potential modifications to the original array or overheads associated with creating new arrays.

Related benchmarks:

Splice vs Spread (immutable only) (version: 0)

Comparing performance of: Splice method vs Spread method

Created: 6 years ago by: Guest

Jump to the latest result

Splice method

Spread method

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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