Benchmark: spread operator vs concat

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 ]

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Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.concat
spread operator

Fastest: N/A

Slowest: N/A

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

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Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches for creating an array by concatenating another array: using the `concat` method (Array.prototype.concat) and using the spread operator (the three dots ...).

**Options Being Compared**

1. **`concat` Method**: This is a traditional way to concatenate arrays in JavaScript. It takes another array as an argument and returns a new array containing all elements from both arrays.
2. **Spread Operator**: The spread operator (... ) creates a new array by taking elements from an existing array or other iterable.

**Pros and Cons of Each Approach**

1. **`concat` Method**:
	* Pros:
		+ Well-established method, widely supported across browsers.
		+ Can be used to create arrays with different data types (e.g., strings, numbers, objects).
	* Cons:
		+ Creates a new array, which can lead to memory allocation overhead.
		+ Requires an explicit method call (`Array.prototype.concat`), making the code slightly less readable.
2. **Spread Operator**:
	* Pros:
		+ More concise and expressive than the `concat` method.
		+ Creates a new array without the need for an explicit method call, reducing overhead.
	* Cons:
		+ Requires support for modern JavaScript features ( ECMAScript 2018 and later).
		+ May not be as widely supported across browsers.

**Library/Functionality Used**

The benchmark uses the `Array.prototype.concat` method, which is a built-in function in JavaScript. The spread operator (`...`) is also a built-in feature introduced in ECMAScript 2015 (ES6).

**Special JS Feature/Syntax**

The benchmark uses the spread operator (`...`), which was introduced in ECMAScript 2018 and later versions. This syntax allows for more concise array creation.

**Other Alternatives**

If you prefer not to use the spread operator or `concat` method, alternative approaches include:

1. Using the `slice()` method: `var other = [1, 2].slice().concat([ "hello", true, 7 ])`
2. Using the `push()` method with a new array: `var other = []; other.push(1, 2); other.push(...[ "hello", true, 7 ])`

Keep in mind that these alternatives may not be as efficient or readable as the spread operator or `concat` method.

**Benchmark Result Interpretation**

The benchmark results show the execution frequency per second for each test case across multiple browsers. In this case:

* The spread operator test resulted in higher execution frequencies, indicating faster performance.
* Chrome 87 achieved better performance than other browsers, likely due to its optimized JavaScript engine.

Please note that benchmarking results can vary depending on the specific environment, browser version, and system configuration.

Related benchmarks:

spread operator vs concat (version: 0)

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

Created: 5 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

No previous run results

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