Benchmark: concat vs spread 22811

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var arr1 = ["what", "is", "this"];
var arr2 = ["this", "is", "a", "test", "hello", "how", "are", "you", "today"];

Tests:

Array.prototype.concat
var result = [arr1, ...arr2]
111
var result = arr1.concat(arr2);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
111

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's dive into the world of MeasureThat.net and understand what's being tested in this benchmark.

**Benchmark Overview**

The benchmark compares two ways to concatenate arrays in JavaScript: using the spread operator (`...`) and the `concat()` method. The test is designed to measure which approach is faster, providing valuable insights for developers who need to optimize their code.

**Options Compared**

1. **Spread Operator (`...`)**: This syntax was introduced in ECMAScript 2015 (ES6) as a new way to concatenate arrays. It works by creating a new array with the elements of the original array followed by the elements of the spreadable value.
2. **`concat()` Method**: This is an older method for concatenating arrays, which creates a new array and copies all elements from both arrays into it.

**Pros and Cons**

**Spread Operator (`...`)**
Pros:

* More concise and readable code
* Creates a new array with minimal overhead
* Works well with other data structures like objects and sets

Cons:

* Can be slower than `concat()` for large arrays due to the overhead of creating a new array
* May not work as expected in older browsers or environments that don't support it

**`concat()` Method**
Pros:

* Well-supported in all major browsers and environments
* Often faster than spread operator for large arrays
* Works well with legacy codebases

Cons:

* More verbose and less readable code
* Creates a new array, which can be slower and more memory-intensive

**Other Considerations**

In modern JavaScript engines, the performance difference between these two approaches is often negligible. However, for certain use cases or applications where every millisecond counts (e.g., real-time analytics, gaming), using the spread operator might result in slightly better performance.

Additionally, the `concat()` method has a higher overhead due to the need to create a new array and copy elements from both arrays, whereas the spread operator only creates a new array with the concatenated elements.

**Library**

In this benchmark, Lodash.js is included as a dependency. Lodash is a popular JavaScript library that provides a lot of utility functions for tasks like string manipulation, array processing, and more. In this specific case, it's used to create a new array using the spread operator (`...`).

**Special JS Feature or Syntax**

There isn't any special JavaScript feature or syntax being tested in this benchmark. The focus is solely on comparing two different approaches for concatenating arrays.

**Alternatives**

Other alternatives for concatenating arrays include:

1. Using the `push()` method to add elements to an array: `arr.push(...arr2)`.
2. Using a loop to iterate over one array and push its elements to another array.
3. Using a library like Lo-Dash (another popular JavaScript utility library) that provides a `concat` function.

These alternatives might have different performance characteristics, syntaxic complexities, or use cases, depending on the specific requirements of your project.

Related benchmarks:

concat vs spread 22811 (version: 0)

Comparing performance of: Array.prototype.concat vs 111

Created: 4 years ago by: Guest

Jump to the latest result

Array.prototype.concat

111

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):