Benchmark: Array concat vs spread operator vs pushxx

Tests:

spread
var params = [ "hello", true, 7 ]; params = [ ...params, "444"];
push
var params = [ "hello", true, 7 ] params.push("444");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
push

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark, "Array concat vs spread operator vs push", compares the performance of three different ways to add an element to an array in JavaScript: the traditional `concat()` method, the ES6 spread operator (`...`), and the `push()` method.

**Benchmark Definition JSON Analysis**

The benchmark definition JSON provides information about the test:

*   The "Name" field indicates that the benchmark is comparing three different approaches.
*   The "Description" field explains that the test compares the new ES6 spread operator with traditional methods (`concat()` and `push()`).
*   The "Script Preparation Code" and "Html Preparation Code" fields are empty, indicating that no specific code needs to be executed before running the benchmark.

**Individual Test Cases**

The individual test cases demonstrate how to add an element to an array using each of the three approaches:

1.  **Spread Operator**: The first test case uses the spread operator (`...`) to add a new element to the `params` array: `var params = [ "hello", true, 7 ]; params = [ ...params, "444"];`.
2.  **Push Method**: The second test case uses the `push()` method to add a new element to the `params` array: `var params = [ "hello", true, 7 ]; params.push("444");`.

**Library and Library Purpose**

In this benchmark, no libraries are explicitly used.

**JavaScript Special Features or Syntax**

The benchmark does not use any special JavaScript features or syntax that would affect its execution. It only uses standard JavaScript constructs.

**Comparison of Approaches**

Here's a comparison of the three approaches:

*   **Traditional `concat()` Method**: This approach creates a new array by concatenating the existing `params` array with the new element (`"444"`). This method has a time complexity of O(n), where n is the length of the original array.
*   **Spread Operator (`...`)**: The spread operator allows you to create a new array from an existing one and adds elements to it. In this case, it creates a new array `[ ...params, "444" ]`, which has a time complexity of O(1), making it more efficient than the `concat()` method for large arrays.
*   **Push Method**: The `push()` method modifies the original array by adding a new element at the end. This approach also has a time complexity of O(n) when considering all elements in the array.

**Pros and Cons**

Here are some pros and cons of each approach:

*   **Traditional `concat()` Method**:
    *   Pros: Simple to use, works well for small arrays.
    *   Cons: Inefficient for large arrays due to its O(n) time complexity.
*   **Spread Operator (`...`)**:
    *   Pros: Efficient for large arrays (O(1) time complexity), concise syntax.
    *   Cons: May require more memory to create a new array, not suitable for very small arrays.
*   **Push Method**:
    *   Pros: Simple to use, efficient for adding elements to the end of an array (O(n) time complexity).
    *   Cons: Modifies the original array, may not be suitable for scenarios where immutability is required.

**Other Alternatives**

Some other alternatives for adding elements to an array in JavaScript include:

*   **Array.prototype.slice()` method with `concat()`: This approach uses `slice()` to create a shallow copy of the array and then concatenates it with the new element using `concat()`. However, this has the same time complexity as the traditional `concat()` method (O(n)).
*   **Array.prototype.unshift()` method: This approach adds elements to the beginning of the array. The time complexity is O(1), making it more efficient than the traditional `concat()` and `push()` methods.

In conclusion, the ES6 spread operator (`...`) is a concise and efficient way to add elements to an array in JavaScript, especially for large arrays. However, when dealing with very small arrays or arrays where immutability is crucial, other approaches like using `push()` or `unshift()` might be more suitable.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:83.0) Gecko/20100101 Firefox/83.0

Browser/OS: Firefox 83 on Windows

View result in a separate tab

Test name	Executions per second
spread	7488295.5 Ops/sec
push	72887304.0 Ops/sec

Related benchmarks:

Array concat vs spread operator vs pushxx (version: 0)

Compare the new ES6 spread operator with the traditional concat() method and push

Comparing performance of: spread vs push

Created: 3 years ago by: Guest

Jump to the latest result

spread

push

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):