Benchmark: Array.prototype.concat vs spread operator not new array

Tests:

Array.prototype.concat
var a = [ "hello", true, 7 ]; var b = [ "hello", true, 7 ]; var c = a.concat(b);
spread operator
var a = [ "hello", true, 7 ]; var b = [ "hello", true, 7 ]; var c = [ ...a, ...b ];

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

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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 their pros/cons.

**Benchmark Overview**

The test compares two approaches to concatenate arrays in JavaScript:

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

**What is being tested?**

The benchmark tests the performance of these two methods on a specific use case: concatenating two identical arrays, `a` and `b`, each containing three elements.

**Options compared**

* `Array.prototype.concat()`: A traditional method for concatenating arrays using the `concat()` function.
* The new ES6 spread operator (`...`): A shorthand syntax for spreading an array into multiple places.

**Pros and Cons of each approach:**

1. **`Array.prototype.concat()`**:
	* Pros:
		+ Widely supported across browsers and versions.
		+ Can handle large arrays efficiently by creating a new array object.
	* Cons:
		+ May create unnecessary intermediate objects in the process.
		+ Can be slower due to the overhead of creating a new array object.
2. **The new ES6 spread operator (`...`)**:
	* Pros:
		+ More concise and expressive syntax.
		+ Creates a shallow copy of the original arrays, which can be faster for small arrays.
	* Cons:
		+ May not work as expected in older browsers or versions that don't support this feature.
		+ Can lead to unexpected behavior if not used carefully.

**Library and purpose**

There is no external library being used in this benchmark. The focus is on the two JavaScript methods themselves.

**Special JS features/syntax**

There are no special JS features or syntaxes being tested beyond the new ES6 spread operator.

**Benchmark preparation code**

The provided `Script Preparation Code` and `Html Preparation Code` are empty, which means the test setup is minimal and focused solely on comparing the performance of the two methods.

**Other alternatives**

To improve performance, developers might also consider:

1. Using `Array.prototype.push()` to concatenate arrays in place.
2. Using `Array.from()` to create a new array from an iterable source (e.g., another array).
3. Using libraries like Lodash or Ramda for more efficient and concise array manipulation.

However, these alternatives are not being tested in this benchmark, which focuses on the comparison between `concat()` and the spread operator.

Related benchmarks:

Array.prototype.concat vs spread operator not new array (version: 0)

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

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

Created: 6 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):