Benchmark: concat vs push - MeasureThat.net

Script Preparation code:

var someBigArray = [];
var anotherArray = [];

for (var i = 0; i < 1000; i++) {
  someBigArray.push(10);
  anotherArray.push(10);
}

Tests:

concat
someBigArray = someBigArray.concat(anotherArray);
push
anotherArray.forEach(function(item) { someBigArray.push(anotherArray); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
push

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

The benchmark we're analyzing is designed to compare two approaches for appending elements to an array: using the `push()` method and using the `concat()` method.

**What is being tested?**

In this benchmark, a large array `someBigArray` is created with 1000 elements. Then, another large array `anotherArray` is created. The test cases are:

1. **concat**: The two arrays are concatenated using the `concat()` method.
2. **push**: The `push()` method is used to append elements from `anotherArray` to `someBigArray`.

**Options being compared**

The benchmark compares the performance of these two approaches: `concat()` and `push()`. We'll explore their pros and cons:

*   **Concat() (Method 1)**:
    *   Pros:
        *   Can be used to append elements from another array.
        *   Often preferred when working with smaller arrays or specific use cases.
    *   Cons:
        *   Creates a new array, which can lead to increased memory usage and slower performance for large datasets.

*   **Push() (Method 2)**:
    *   Pros:
        *   Modifies the original array in-place, reducing memory usage and potentially improving performance for large arrays.
        *   Suitable when working with existing arrays that need to be appended to.
    *   Cons:
        *   Only applicable for appending elements from another array (`anotherArray` in this case).
        *   Might lead to slower performance if not optimized properly.

**Other considerations**

When using `push()`, it's essential to ensure that the original array has enough capacity to accommodate new elements, as excess memory allocation can slow down performance. This is often achieved by using methods like `slice()` or creating a copy of the original array before appending new elements.

For large datasets, the difference between these approaches might not be significant, but for smaller arrays or specific use cases, one method may outperform the other.

**Library and special JS feature**

There are no libraries used in this benchmark. However, JavaScript features like arrow functions (e.g., `someBigArray.forEach(function(item) {...})`) are utilized.

**Alternatives**

Other alternatives to these approaches include:

*   Using a library or framework that provides optimized array append methods.
*   Utilizing `at()` method for sparse arrays, which allows appending elements without creating a new array.
*   Leveraging Web Workers or parallel processing for faster performance when working with large datasets.

Keep in mind that the choice of approach depends on the specific use case and requirements of your project. This benchmark provides a basic comparison to help you decide which method is more suitable for your needs.

Related benchmarks:

concat vs push (version: 0)

Comparing performance of: concat vs push

Created: 9 years ago by: Guest

Jump to the latest result

concat

push

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):