Benchmark: Array.prototype.concat vs spread

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

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros/cons.

**Benchmark Definition**

The website is testing two approaches to concatenate arrays in JavaScript: using the traditional `concat()` method versus the new ES6 spread operator (`...`). This comparison is intended to measure performance differences between these two methods.

**Options Compared**

* Traditional `Array.prototype.concat()`
* New ES6 spread operator (`...`)

**Pros and Cons of Each Approach**

1. **Traditional `Array.prototype.concat()`:**
	* Pros:
		+ Widely supported across older browsers and versions.
		+ Can be used to concatenate arrays with other array methods (e.g., `push()`).
	* Cons:
		+ Performance overhead due to creating a new array object and iterating over the original arrays.
		+ May lead to increased memory usage if not handled correctly.
2. **New ES6 spread operator (`...`):**
	* Pros:
		+ More readable and concise syntax for concatenating arrays.
		+ Often faster performance since it uses destructuring under the hood, which is optimized by modern JavaScript engines.
	* Cons:
		+ Requires modern browsers or versions that support the ES6 specification (which is a significant portion of modern web development).
		+ May not work as expected in older browsers or environments.

**Library and Purpose**

There are no specific libraries mentioned in the benchmark definition. However, it's worth noting that the spread operator relies on some underlying JavaScript features, such as:

* Destructuring (ECMAScript 2015)
* Rest parameter syntax (`...`)

These features are part of the ES6 specification and have been widely adopted in modern web development.

**Special JS Feature or Syntax**

The benchmark uses the new ES6 spread operator (`...`), which is a relatively recent addition to the JavaScript language. This feature allows for more concise array concatenation, as seen in the example: `var other = [ 1, 2, ...params ];`. The spread operator has been supported by most modern browsers since around 2015.

**Other Alternatives**

If you're looking for alternative ways to concatenate arrays in JavaScript without using the spread operator or `concat()`, some options include:

* Using `Array.prototype.push()`:
```javascript
var other = [];
other.push(...params);
```
This method creates a new array object and pushes each element from `params` onto it.
* Using `Array.prototype.slice()` with `concat()`:
```javascript
var other = Array.prototype.slice.call(params).concat([ 1, 2 ]);
```
However, these alternatives may not be as concise or performant as the spread operator or `concat()`.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36

Browser/OS: Chrome 78 on Linux

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	8434803.0 Ops/sec
spread operator	34003164.0 Ops/sec

Related benchmarks:

Array.prototype.concat vs spread (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):