Benchmark: splice VS index 3

Script Preparation code:

var list = [];
for (var i = 0; i < 2000; i++) {
  list.push(i);
}

Tests:

splice
list.splice(1001, 0, 'movedElement');
index
list[1001] = 'movedElement';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splice
index

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser/OS: Chrome 127 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
splice	18236.2 Ops/sec
index	25988952.0 Ops/sec

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, compared options, pros and cons, and other considerations.

**Benchmark Overview**

The benchmark is designed to measure the performance difference between two approaches: `splice` and using an index (`index 3`) to replace an element in a large array. The test case uses JavaScript, specifically, to demonstrate these differences.

**Script Preparation Code**

The script preparation code creates a large array of 2000 elements, initialized with integers from 0 to 1999.
```javascript
var list = [];
for (var i = 0; i < 2000; i++) {
  list.push(i);
}
```
This array will be used as the input for both test cases.

**Html Preparation Code**

There is no HTML preparation code provided, which means the benchmark assumes a basic JavaScript execution environment and does not account for any additional overhead due to rendering or other non-JavaScript aspects of web pages.

**Test Cases**

The benchmark consists of two individual test cases:

1. **splice**: This test case uses the `splice` method to replace an element at index 1001 with a new string value `'movedElement'`.
```javascript
list.splice(1001, 0, 'movedElement');
```
2. **index**: This test case uses direct array indexing (`list[1001]`) to replace an element at the same index with a new string value `'movedElement'`.
```javascript
list[1001] = 'movedElement';
```
**Library and Purpose**

In this benchmark, no external libraries are used. The `splice` method is a built-in JavaScript function that modifies the array by removing and replacing elements.

**Special JS Features or Syntax (None)**

There are no special JavaScript features or syntax being tested in this benchmark.

**Pros and Cons of Each Approach**

1. **splice**:
	* Pros:
		+ Can replace multiple elements at once.
		+ Less prone to off-by-one errors.
	* Cons:
		+ Can be slower due to the overhead of shifting elements when replacing multiple elements.
2. **index**:
	* Pros:
		+ Typically faster, as it avoids the overhead of shifting elements.
	* Cons:
		+ More error-prone, as off-by-one errors can occur if the index is incorrect.

**Considerations**

When choosing between `splice` and direct indexing for array manipulation, consider the trade-offs between speed, safety, and code readability. If you need to replace multiple elements or want a more robust solution, `splice` might be the better choice. However, if performance is critical and you're working with large arrays, direct indexing (`index`) could be faster.

**Other Alternatives**

If you need to manipulate arrays frequently, other approaches like using slicing (`list.slice()`) or `forEach()` with a callback function might also be considered. These methods can provide similar functionality but may have different performance characteristics.

Keep in mind that the actual performance differences between these approaches will depend on the specific use case and the JavaScript engine being used.

Related benchmarks:

splice VS index 3 (version: 2)

Comparing performance of: splice vs index

Created: one year ago by: Registered User

Jump to the latest result

splice

index

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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