Benchmark: Array.prototype.concat vs sequential spread operator

Tests:

Array.prototype.concat
var arr1 = Array(100).fill("abc"); var arr2 = Array(10).fill("abc"); var arr3 = arr1.concat(arr2);
spread operator
var arr1 = Array(100).fill("abc"); var arr2 = Array(10).fill("abc"); var arr3 = [...arr1, ...arr2];

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Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

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

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Let's dive into the benchmarking test.

**What is being tested?**

The provided JSON represents two JavaScript microbenchmarks: `Array.prototype.concat` and `sequential spread operator`. The tests aim to compare the performance of these two approaches when concatenating arrays in JavaScript.

**Options compared**

Two options are being compared:

1. **`Array.prototype.concat()`**: A traditional method for concatenating arrays, which creates a new array by copying elements from the source arrays.
2. **Sequential spread operator (`...`)**: The new ES6 spread operator, introduced in ECMAScript 2015 (ES6), allows for the creation of new arrays by spreading elements from existing arrays.

**Pros and Cons**

* **`Array.prototype.concat()`**
	+ Pros:
		- Widely supported across browsers and Node.js versions.
		- Easy to implement and understand.
	+ Cons:
		- Creates a new array, which can lead to memory allocation overhead.
		- May be slower than the spread operator due to its iterative nature.
* **Sequential spread operator (`...`)**
	+ Pros:
		- More concise and expressive than `concat()`.
		- Can be faster because it avoids the creation of a temporary array.
	+ Cons:
		- Not as widely supported across older browsers and Node.js versions.

**Library usage**

Neither of the tested libraries is explicitly mentioned, but both methods rely on the JavaScript engine's internal implementation. However, if we consider external libraries or frameworks that might use these methods, some examples include:

* Lodash: A popular utility library that often uses `concat()` for array concatenation.
* React: A front-end framework that occasionally uses the spread operator to create new arrays.

**Special JS feature or syntax**

The tests utilize a special JavaScript feature: **spread operator (`...`)**, introduced in ES6. This operator allows for the creation of new arrays by spreading elements from existing arrays.

Other alternatives to these methods include:

* `Array.prototype.push()`: While not as concise, this method can be used for array concatenation.
* Using `String.join()` or other string concatenation methods: Not suitable for general-purpose array concatenation, but might be useful in specific cases.

**Benchmark result analysis**

The provided benchmark results show that the sequential spread operator (`...`) outperforms the traditional `Array.prototype.concat()` method on this test case. This is likely due to the latter's overhead of creating a temporary array and the former's ability to use a more efficient, in-place concatenation algorithm.

Keep in mind that these results may vary depending on specific use cases, browsers, Node.js versions, and hardware configurations.

When writing your own benchmarks or performance tests, consider factors like:

* Test case specificity
* Browser/Node.js version support
* Memory allocation and garbage collection overhead
* Code conciseness and readability
* Use of special features or syntax

This should provide a solid foundation for understanding the benchmarking test and its results.

Related benchmarks:

Array.prototype.concat vs sequential spread operator (version: 0)

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

Comparing performance of: Array.prototype.concat vs spread operator

Created: 4 years ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

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):