Benchmark: Array.prototype.concat vs double spread operator

Tests:

Array.prototype.concat
const params = ["hello", true, 7]; const initial = [1, 2]; const other = initial.concat(params);
spread operator
const params = ["hello", true, 7]; const initial = [1, 2]; const other = [...initial, ...params ]

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Suite status: <idle, ready to run>

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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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**What is being tested?**

The provided benchmark tests two approaches for creating an array by concatenating another array with some additional elements:

1. **`Array.prototype.concat()`**: This method creates a new array and copies all elements from the original array (`initial`) and the concatenated array (`params`) into it.
2. **Double spread operator (Rest Operator)**: This operator allows you to create an array by spreading its elements using the `...` syntax.

**Options compared**

The benchmark compares the performance of these two approaches:

* `Array.prototype.concat()`: The traditional method for concatenating arrays in JavaScript.
* Double spread operator (`[...]`): The new ES6 feature that allows creating an array by spreading its elements.

**Pros and Cons:**

* **`Array.prototype.concat()`**: Pros:
	+ Well-established, widely supported method.
	+ Can be more readable when used with other methods like `slice()` or `push()`.
	Cons:
	+ Creates a new array, which can lead to performance issues for large datasets.
	+ Can be slower than the spread operator due to its overhead.
* **Double spread operator (`[...]`)**: Pros:
	+ More concise and readable way to create an array.
	+ Can lead to better performance for large datasets since it avoids creating a new array.
Cons:
	+ Less widely supported (older browsers might not support it).
	+ May require more memory allocation.

**Other considerations**

When choosing between these two approaches, consider the size of your dataset and the performance requirements of your application. If you're working with small to medium-sized arrays, the spread operator might be a better choice. However, if you need to concatenate very large datasets, `Array.prototype.concat()` might be more suitable.

**Library usage**

There is no library used in this benchmark.

**Special JS feature or syntax**

The benchmark uses the double spread operator (`[...]`), which was introduced in ECMAScript 2015 (ES6). This feature allows creating an array by spreading its elements using the `...` syntax. The spread operator has become widely supported in modern browsers and JavaScript engines.

**Other alternatives**

If you're looking for alternative approaches to concatenate arrays, consider using:

* `Array.prototype.push()` with multiple arguments: `initial.push(...params)`
* Using a library like Lodash's `concat` function
* Using an array comprehension (available in some JavaScript engines or libraries)

Keep in mind that each approach has its pros and cons, and the choice ultimately depends on your specific use case and performance requirements.

Related benchmarks:

Array.prototype.concat vs double spread operator (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

No previous run results

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