Benchmark: Array.prototype.concat vs spread operator (fix)

Script Preparation code:

var params = [ "hello", true, 7 ];

Tests:

Array.prototype.concat
var other = [ 1, 2 ].concat(params);
spread operator
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: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36

Browser/OS: Chrome 139 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	27993874.0 Ops/sec
spread operator	85154752.0 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 benchmark and explain what's being tested.

**Benchmark Definition**

The benchmark is comparing two approaches to concatenate arrays in JavaScript: `Array.prototype.concat()` method and the new ES6 spread operator (`...`). The script preparation code defines an array `params` with three elements: "hello", `true`, and `7`.

**Options Compared**

Two options are being compared:

1. **`Array.prototype.concat()`**: This is a traditional method for concatenating arrays, which involves creating a new array object by combining the original array with another array.
2. **Spread Operator (`...`)**: This is a new syntax introduced in ES6 that allows you to create a new array by spreading elements from an existing array.

**Pros and Cons**

* **`Array.prototype.concat()`**:
	+ Pros: widely supported, easy to understand for those familiar with JavaScript arrays.
	+ Cons: can be slower than the spread operator due to its more complex implementation (creating a new array object).
* **Spread Operator (`...`)**:
	+ Pros: generally faster, more concise and readable, especially in modern browsers that support it well.
	+ Cons: less widely supported, may not work as expected in older browsers or environments.

**Library**

None. This benchmark uses only built-in JavaScript functionality.

**Special JS Feature/Syntax**

No special features or syntax are used beyond the spread operator.

**Other Alternatives**

* **Array.prototype.push()**: Another common way to concatenate arrays in JavaScript, which would involve creating an array and then pushing elements onto it.
* **Array.concat() with a function**: Creating a function that takes an array as input and returns a new concatenated array.

Related benchmarks:

Array.prototype.concat vs spread operator (fix) (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):