Benchmark: Array concat vs spread operator [1]

Tests:

Array.prototype.concat
var params = [ "hello", true, 7 ]; var other = [ 1, 2 ].concat(params);
spread operator
var params = [ "hello", true, 7 ] var other = [ 1, 2, ...params ]

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

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser/OS: Chrome 83 on Mac OS X 10.15.5

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	7044651.0 Ops/sec
spread operator	31730898.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark in detail.

**Benchmark Definition**

The benchmark compares two ways to concatenate arrays in JavaScript: the traditional `concat()` method and the new ES6 spread operator (`...`). This is done using a simple test case where an array of strings, booleans, and numbers is passed as an argument to the concatenation operation.

**Script Preparation Code and Html Preparation Code**

Since there are no script or HTML preparation codes provided in the benchmark definition, this means that the test cases should be executed from scratch on each run. The test results will likely depend on various factors such as browser version, operating system, device platform, etc.

**Individual Test Cases**

The two test cases are:

1. **Array.prototype.concat**
```javascript
var params = [ "hello", true, 7 ];
var other = [ 1, 2 ].concat(params);
```
This test case creates an array `other` by concatenating the array `[ 1, 2 ]` with another array `params`. The `concat()` method is a built-in method of the `Array.prototype`.

2. **Spread Operator**
```javascript
var params = [ "hello", true, 7 ];
var other = [ 1, 2, ...params ];
```
This test case creates an array `other` by using the spread operator (`...`) to concatenate the elements of the array `params` with another array `[ 1, 2 ]`. The spread operator is a new feature introduced in ES6.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **Array.prototype.concat**
	+ Pros:
		- Widely supported by older browsers
		- Familiar syntax for many developers
	+ Cons:
		- Can be slower than the spread operator due to the overhead of method calls
		- May have performance issues in certain edge cases (e.g., very large arrays)
* **Spread Operator**
	+ Pros:
		- Faster and more efficient than `concat()`
		- Simplifies code and reduces the number of method calls
	+ Cons:
		- Only supported by modern browsers and some older versions
		- May have compatibility issues with certain libraries or frameworks

**Library Used**

None. The benchmark uses only built-in JavaScript features.

**Special JS Features or Syntax**

The spread operator (`...`) is a new feature introduced in ES6, which allows for more concise syntax when working with arrays and objects.

**Alternatives**

If you want to run this benchmark on an older browser that doesn't support the spread operator, you could use alternative approaches such as:

* Using `Array.prototype.push()` method to concatenate elements
* Using `Array.prototype.join()` method to concatenate elements (although this would require additional work to join strings with commas)
* Rewriting the code using a different library or framework that supports the spread operator

Keep in mind that these alternatives may introduce significant changes to the benchmark's behavior and results.

Related benchmarks:

Array concat vs spread operator [1] (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>

Experimental features:

Fastest: N/A

Slowest: N/A

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