Benchmark: New array using two slices vs one slice plus overwrite 2

Tests:

Override
const a = [{a: 1}, {a: 2}, {a: 3}, {a: 4}, {a: 5}, {a: 6}]; const b = a.slice(); b[1] = {a: 'x'};
Separate slices
const a = [{a: 1}, {a: 2}, {a: 3}, {a: 4}, {a: 5}, {a: 6}]; const b = [...a.slice(0, 1), {a: 'x'}, ...a.slice(2)];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Override
Separate slices

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is defined using JSON, which provides information about the test case. Here's a summary:

* `Name`: The name of the benchmark, which is "New array using two slices vs one slice plus overwrite 2".
* `Description`: An empty description.
* `Script Preparation Code` and `Html Preparation Code`: Empty strings, indicating that no special setup or HTML code is required for this test.

**Individual Test Cases**

There are only two test cases:

1. **Override**: This test case uses a script with the following content:
```javascript
const a = [{a: 1}, {a: 2}, {a: 3}, {a: 4}, {a: 5}, {a: 6}];
const b = a.slice();
b[1] = {a: 'x'};
```
This script creates an array `a` with six elements, then creates a new slice of the array using `slice()`. Finally, it overwrites the second element of the slice (`b`) with a new object.

2. **Separate slices**: This test case uses a script with the following content:
```javascript
const a = [{a: 1}, {a: 2}, {a: 3}, {a: 4}, {a: 5}, {a: 6}];
const b = [...a.slice(0, 1), {a: 'x'}, ...a.slice(2)];
```
This script creates an array `a` with six elements, then uses the spread operator (`...`) to create a new array `b`. The first element of `a` is taken from the first slice using `slice(0, 1)`, and a new object is added at the second position. The remaining elements are taken from the last two slices using `a.slice(2)`.

**Library: none**

Neither test case uses any external libraries or dependencies.

**Special JavaScript features/syntax: None**

Neither test case uses any special JavaScript features or syntax that would affect the execution.

**What's being tested?**

The benchmark is testing the performance difference between two approaches:

1. **Override**: This approach involves creating a new slice of an array and then modifying the second element of the slice.
2. **Separate slices**: This approach involves using the spread operator to create a new array by concatenating three parts:
	* The first part takes elements from the first slice using `slice(0, 1)`.
	* The second part adds a new object at the second position.
	* The third part takes elements from the last two slices using `a.slice(2)`.

**Pros and cons:**

The pros and cons of these approaches are:

**Override**:

Pros:

* Simple to understand and implement
* Only modifies the original array

Cons:

* Creates a new slice, which can lead to additional memory allocations
* Modifying the second element of the slice may not be efficient if the array is large

**Separate slices**:

Pros:

* Avoids creating a new slice, reducing memory allocations
* Allows for more control over the resulting array structure

Cons:

* Requires using the spread operator, which can be less intuitive
* Creates a new array, which can lead to additional memory allocations if not done carefully

**Other alternatives:**

There are other ways to achieve similar results, such as:

* Using `Array.prototype.reduce()` or `Array.prototype.forEach()` to iterate over the elements of the array and perform operations on each element.
* Using a loop with indexing to access and modify specific elements of the array.

However, these approaches may have different performance characteristics and are not directly comparable to the `Override` and `Separate slices` methods.

Related benchmarks:

New array using two slices vs one slice plus overwrite 2 (version: 0)

Comparing performance of: Override vs Separate slices

Created: 7 years ago by: Guest

Jump to the latest result

Override

Separate slices

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):