Benchmark: Array concat vs spread items test

Tests:

Array.prototype.concat
const arr = Array.from({ length: 50 }).map((i, index) => ({id: index, name: `name for ${index}`})); const arr2 = Array.from({ length: 50 }).map((i, index) => ({id: 50 + index, name: `name for ${50 + index}`})); return arr.concat(arr2);
spread operator
const arr = Array.from({ length: 50 }).map((i, index) => ({id: index, name: `name for ${index}`})); const arr2 = Array.from({ length: 50 }).map((i, index) => ({id: 50 + index, name: `name for ${50 + index}`})); return [...arr, ...arr2];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript microbenchmarking test created on MeasureThat.net. This test compares the performance of two approaches: using the traditional `concat()` method and pushing items to an array, versus using the new ES6 spread operator (`...`) to concatenate arrays.

**Options being compared:**

1. **Traditional concat() method**: This approach uses the `concat()` method to combine two arrays.
2. **Spread operator**: This approach uses the `...` spread operator to concatenate two arrays.

**Pros and Cons of each approach:**

* Traditional concat() method:
	+ Pros: Well-established, widely supported, and easy to understand.
	+ Cons: Can be slower than the spread operator, especially for large arrays.
* Spread operator:
	+ Pros: More modern and efficient, reduces memory allocation, and can be faster for large arrays.
	+ Cons: May not work correctly with older browsers or JavaScript versions that do not support it.

**Library/Language features used in the test case:**

* None mentioned, as this is a basic JavaScript benchmarking test.

**Special JS feature or syntax used:**

The spread operator (`...`) introduced in ES6 (ECMAScript 2015) allows for more concise and expressive array creation and manipulation. It's a modern feature that's widely supported in modern browsers and JavaScript engines.

**Other alternatives:**

In addition to the traditional concat() method and the spread operator, there are other approaches to concatenate arrays, such as:

* `Array.prototype.push.apply()` (pushing all elements from one array to another)
* `Array.prototype.splice()` (modifying an existing array by inserting new elements)

However, these alternatives might not be as efficient or readable as the traditional concat() method and the spread operator.

**Benchmark preparation code explanation:**

The provided benchmark definitions create two arrays (`arr` and `arr2`) with 50 elements each. Each element is an object with an `id` and a `name`. The benchmark then concatenates these two arrays using both the traditional concat() method and the spread operator, and measures their performance.

**Latest benchmark result:**

The latest benchmark results show that the spread operator outperforms the traditional concat() method in terms of executions per second (e.g., 282612.5 vs. 269879.21875 for Chrome 116 on a Mac OS X 10.15.7 device).

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	282612.5 Ops/sec
spread operator	269879.2 Ops/sec

Related benchmarks:

Array concat vs spread items test (version: 0)

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

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

Created: one year ago by: Guest

Jump to the latest result

Array.prototype.concat

spread operator

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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