Benchmark: Concat vs Spread on two arrays

Tests:

spread
var a = [ "hello", true, 7 ] var b = [ "hello2", true, 27 ] var other = [ ...a, ...b ]
concat
var a = [ "hello", true, 7 ] var b = [ "hello2", true, 27 ] var other = a.concat(b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
concat

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**What is being tested?**

The benchmark compares two ways to concatenate arrays in JavaScript: using the spread operator (`...`) and using the `concat()` method.

**Options compared:**

* Using the spread operator (`...`) to create a new array by copying elements from another array.
* Using the `concat()` method to concatenate two arrays and return a new array.

**Pros and Cons of each approach:**

1. **Spread Operator (``)**
	* Pros:
		+ More concise and expressive way to create a new array by spreading elements from an existing array.
		+ Can be faster for large arrays, as it avoids the overhead of function calls and method lookups.
	* Cons:
		+ Introduced in ECMAScript 2015 (ES6), so may not support older browsers or versions of JavaScript.
		+ May not be supported in older browsers that don't have modern JavaScript implementations.
2. **Concat() Method**
	* Pros:
		+ Widespread support across browsers and versions of JavaScript.
		+ Well-established method, making it easier for developers to understand and use.
	* Cons:
		+ Less concise than the spread operator syntax, which can make code harder to read.
		+ May be slower for large arrays due to function call overhead.

**Other considerations:**

* The benchmark uses a relatively small array size (`[2]`) to test performance. For larger arrays or more complex scenarios, the results may differ significantly.
* Both methods create a new array, which can lead to increased memory usage and garbage collection.

**Library/Functionality used:**

None in this specific benchmark.

**Special JavaScript feature/syntax:**

The spread operator (`...`) is not special to this benchmark but was introduced in ECMAScript 2015 (ES6). It's a new syntax for creating arrays or objects by spreading elements from existing arrays or objects.

**Alternatives:**

Other ways to concatenate arrays in JavaScript include:

1. **Array.prototype.push()**: Using the `push()` method to add elements to an array and then reassigning the result to a variable.
```javascript
var a = [ 'hello' ];
a.push( true );
a.push( 7 );
```
2. **Array.prototype.join()**: Using the `join()` method to concatenate arrays, but this is more suitable for strings than arrays.
```javascript
var a = ['hello', true, 7];
var result = a.join(', ');
```
These alternatives may not be as efficient or concise as the spread operator and `concat()` methods.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Browser/OS: Chrome 68 on Mac OS X 10.12.6

View result in a separate tab

Test name	Executions per second
spread	14871437.0 Ops/sec
concat	5149102.5 Ops/sec

Related benchmarks:

Concat vs Spread on two arrays (version: 0)

Comparing performance of: spread vs concat

Created: 6 years ago by: Guest

Jump to the latest result

spread

concat

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):