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

Tests:

Array.prototype.concat
let params = [ "hello", true, 7 ]; let other = [ 1, 2 ].concat(params);
spread operator
let params = [ "hello", true, 7 ] let 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 benchmarking data to understand what's being tested and compared.

**Benchmark Overview**

The test compares two approaches for concatenating arrays in JavaScript: the traditional `Array.prototype.concat()` method and the new ES6 spread operator (`...`).

**Options Compared**

Two options are compared:

1. **`Array.prototype.concat()`**: This is a built-in method in JavaScript that concatenates one or more arrays into a single array.
2. **Spread Operator (`...`)**: Introduced in ECMAScript 2015 (ES6), the spread operator is used to expand an array (or an object) into separate arguments.

**Pros and Cons of Each Approach**

1. **`Array.prototype.concat()`**:
	* Pros:
		+ Well-established and widely supported.
		+ Can handle large arrays efficiently due to its optimized implementation.
	* Cons:
		+ May have overhead due to method call and argument passing.
		+ Less readable code compared to the spread operator.
2. **Spread Operator (`...`)**:
	* Pros:
		+ More concise and readable code.
		+ No function call or argument passing overhead.
	* Cons:
		+ Less supported in older browsers (pre-ES6) or versions of JavaScript.
		+ May have performance overhead due to array expansion.

**Library and Special JS Feature**

There is no library used in this benchmark. However, the spread operator is a special feature introduced in ECMAScript 2015 (ES6).

**Benchmark Preparation Code**

The script preparation code is not provided for each test case, but it's likely that both `concat()` and the spread operator are used with a similar setup to test their performance.

**Individual Test Cases**

Two test cases are defined:

1. **`Array.prototype.concat()`**: Tests the concatenation of two arrays: `[ 1, 2 ]` and an array containing strings (`"hello"`, `true`, `7`).
2. **Spread Operator**: Tests the same concatenation as above using the spread operator (`[ ...params ]`).

**Latest Benchmark Result**

The benchmark results show that the spread operator outperforms `Array.prototype.concat()` in this test, with a higher number of executions per second.

**Other Alternatives**

If you want to explore alternative approaches for array concatenation, consider:

* Using `Array.prototype.push()`: This method appends elements to an array and returns the new length. It's less efficient than `concat()` or the spread operator.
* Using `Array.prototype.splice()`: This method removes and replaces elements from an array. While it can be used for concatenation, it's not as straightforward as `concat()` or the spread operator.
* Implementing custom concatenation logic: Depending on your specific use case, you might consider writing a custom function to concatenate arrays, which could potentially offer better performance.

Keep in mind that performance differences between these approaches may vary depending on your specific JavaScript version, browser, and hardware.

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36

Browser/OS: Chrome 104 on Windows

View result in a separate tab

Test name	Executions per second
Array.prototype.concat	8239260.0 Ops/sec
spread operator	31230934.0 Ops/sec

Related benchmarks:

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

Compare the new ES6 spread operator with the traditional concat() method. Forked to get rid of jQuery test.

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

Created: 2 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):