Benchmark: list push vs splice

Script Preparation code:

l = 123;

Tests:

append
a = Array(l); a.push(3);
splice
a = Array(l); a.splice(0,0,3);
reverse
a = Array(l); a.reverse().push(3); a.reverse();
concat
a = Array(l); a = [3].concat(a);
unshift
a = Array(l); a.unshift(3);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
append
splice
reverse
concat
unshift

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 26 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
append	2707599.0 Ops/sec
splice	2158034.0 Ops/sec
reverse	1691991.4 Ops/sec
concat	2257484.2 Ops/sec
unshift	2797324.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared options, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark definition is represented by a JSON object that contains information about the test case:
```json
{
    "Name": "list push vs splice",
    "Description": null,
    "Script Preparation Code": "l = 123;",
    "Html Preparation Code": null
}
```
In this case, the script preparation code initializes an array `l` with a large value (123). This is done to ensure that the arrays are large enough to cause significant performance differences when performing push and splice operations.

**Individual Test Cases**

The benchmark consists of five test cases:
```json
[
    {
        "Benchmark Definition": "a = Array(l);\r\na.push(3);",
        "Test Name": "append"
    },
    {
        "Benchmark Definition": "a = Array(l);\r\na.splice(0,0,3);",
        "Test Name": "splice"
    },
    {
        "Benchmark Definition": "a = Array(l);\r\na.reverse().push(3);\r\na.reverse();",
        "Test Name": "reverse"
    },
    {
        "Benchmark Definition": "a = Array(l);\r\na = [3].concat(a);",
        "Test Name": "concat"
    },
    {
        "Benchmark Definition": "a = Array(l);\r\na.unshift(3);",
        "Test Name": "unshift"
    }
]
```
Each test case is a simple JavaScript operation that is performed on an array `l` initialized with a large value. The operations are:

1. **Append**: Using the `push()` method to add an element to the end of the array.
2. **Splice**: Using the `splice()` method to insert an element at the beginning of the array.
3. **Reverse** and **Push**: Reversing the array, pushing an element onto the end, and then reversing the array again (to check if the push operation is actually performed).
4. **Concat**: Creating a new array by concatenating `[3]` with the original array `a`.
5. **Unshift**: Using the `unshift()` method to add an element to the beginning of the array.

**Comparison**

The benchmark compares the performance of each test case across different browsers and devices. The comparison is done using the following metrics:

* **RawUAString**: The User Agent string of the browser being tested.
* **Browser**: The name of the browser being tested (in this case, Firefox 130).
* **DevicePlatform**: The type of device being tested (Desktop in this case).
* **OperatingSystem**: The operating system being tested (Windows in this case).
* **ExecutionsPerSecond**: The number of executions per second for each test case.

**Options Compared**

The benchmark compares the performance of five different approaches:

1. **Push**: Using the `push()` method to add an element to the end of the array.
2. **Splice**: Using the `splice()` method to insert an element at the beginning of the array.
3. **Reverse + Push**: Reversing the array, pushing an element onto the end, and then reversing the array again (to check if the push operation is actually performed).
4. **Concat**: Creating a new array by concatenating `[3]` with the original array `a`.
5. **Unshift**: Using the `unshift()` method to add an element to the beginning of the array.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Push**:
	* Pros: Fast, efficient, and widely supported.
	* Cons: May not work as expected if the array is very large or has a lot of elements.
2. **Splice**:
	* Pros: Allows for more control over insertion point and can be faster than push for small arrays.
	* Cons: Can be slower than push for large arrays due to the overhead of removing elements from the array.
3. **Reverse + Push**:
	* Pros: Verifies that the push operation is actually performed, which can be useful in certain scenarios.
	* Cons: Slower than pure push operations due to the additional reversal steps.
4. **Concat**:
	* Pros: Creates a new array without modifying the original one, which can be useful for preserving data integrity.
	* Cons: Can be slower than push or splice operations for large arrays due to the overhead of creating a new array.
5. **Unshift**:
	* Pros: Allows for more control over insertion point and can be faster than push for small arrays.
	* Cons: Slower than push for large arrays due to the overhead of removing elements from the array.

**Other Considerations**

Some other considerations when working with JavaScript arrays include:

* **Array length**: The performance of operations like push, splice, and unshift can vary depending on the length of the array. For very large arrays, these operations may become slower than others.
* **Browser support**: Different browsers may have different implementations of array methods, which can affect their performance. It's essential to test your code across multiple browsers to ensure compatibility and optimal performance.
* **ES6+ features**: If you're using modern JavaScript versions (ECMAScript 2015 or later), you may be able to take advantage of new features like `Array.prototype.includes()` or `Array.prototype.findIndex()`, which can improve the performance of certain operations.

**Alternatives**

If you need to optimize array operations in your code, here are some alternative approaches:

* **Native WebAssembly**: Using native WebAssembly instructions for array operations can provide significant performance improvements.
* ** SIMD (Single Instruction, Multiple Data)**: Leveraging SIMD instructions like SSE or AVX for array operations can take advantage of parallel processing and improve performance.

Keep in mind that these alternatives may require more complex code and additional setup, so it's essential to carefully evaluate their benefits and trade-offs before implementing them.

Related benchmarks:

list push vs splice (version: 6)

Comparing performance of: append vs splice vs reverse vs concat vs unshift

Created: 3 years ago by: Registered User

Jump to the latest result

append

splice

reverse

concat

unshift

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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