Benchmark: Array.prototype.concat vs spread operator (new try)

Tests:

Array.prototype.concat
var array = [ 1, 2 ]; var other = [ ...array, 3 ];
spread operator
var array = [ 1, 2 ]; var other = array.concat(3);

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: 8 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36

Browser/OS: Chrome 139 on Windows

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	44223792.0 Ops/sec
spread operator	8404415.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and other considerations.

**What's being tested?**

The benchmark is comparing two approaches to concatenate arrays in JavaScript:

1. The traditional `Array.prototype.concat()` method
2. The new ES6 spread operator (`...`)

**Options compared:**

* `Array.prototype.concat()`: This method takes one or more arrays as arguments and returns a new array that contains all the elements of the input arrays.
* Spread operator (`...`): This operator allows you to expand an array into its constituent elements, which can then be used in various contexts.

**Pros and Cons:**

* `Array.prototype.concat()`: Pros:
	+ Well-established and widely supported method
	+ Easy to understand and use for simple concatenations
* Cons:
	+ Can be slower than the spread operator for large arrays due to its overhead
	+ May have performance implications in certain scenarios (e.g., when used with large arrays or as a loop variable)
* Spread operator (`...`):
	+ Pros:
		- Faster than `concat()` for large arrays
		- More concise and expressive syntax
	+ Cons:
		- May be less familiar to older developers or those not well-versed in ES6 features

**Library and purpose:**

None mentioned in the provided benchmark definition, but it's worth noting that neither `Array.prototype.concat()` nor the spread operator relies on any external libraries.

**Special JS feature/syntax:**

The use of the spread operator (`...`) is a notable example of a newer JavaScript feature. The spread operator is an ES6 syntax that was introduced to simplify array manipulation and other contexts where arrays are used as values or arguments.

**Other alternatives:**

Before the spread operator became widely adopted, developers often used various methods for concatenating arrays, such as:

* `Array.prototype.push()`: Adding elements to the end of an array using `push()` instead of `concat()`.
* `Array.prototype.splice()`: Using `splice()` to remove and replace elements within an array.
* Manual string or array concatenation using loops or iteration.

These alternatives are still valid approaches but may have different performance characteristics, readability, and maintainability compared to the spread operator and traditional `concat()` method.

Related benchmarks:

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

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

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

Created: 3 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

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