Benchmark: push vs spread vs concat two big arrays 2

Tests:

push
const n = 10000; const a1 = Array(n).fill(2); const a2 = Array(n).fill(3); a1.push(...a2);
spread
const n = 10000; const a1 = Array(n).fill(2); const a2 = Array(n).fill(3); [...a1,...a2]
concat
const n = 10000; const a1 = Array(n).fill(2); const a2 = Array(n).fill(3); a1.concat(a2);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
spread
concat

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 definition and test cases to understand what is being tested.

**Overview**

The benchmark measures the performance of three different approaches for concatenating two large arrays in JavaScript:

1. `push`
2. `spread` (using the spread operator `...`)
3. `concat`

These approaches are compared to determine which one is the fastest on a specific browser and device configuration.

**Library usage**

In this benchmark, no libraries are explicitly used beyond the standard JavaScript features being tested. However, it's worth noting that modern browsers often have built-in optimizations for certain operations, such as array concatenation, which may affect the results.

**Special JS feature**

The `spread` operator (`...`) is a relatively recent addition to the JavaScript language (introduced in ECMAScript 2015). It allows for more concise and expressive code, but its performance impact is still being evaluated and optimized by browsers.

Here's a brief overview of each approach:

1. **push**: This method uses the `push()` method to add elements to an array and then updates the length of the array. This approach can be slower due to the overhead of updating the array's length.
2. **spread**: This method uses the spread operator (`...`) to create a new array by copying elements from two existing arrays. This approach is generally faster than `push` because it avoids the need for updating the array's length.
3. **concat**: This method uses the `concat()` method to concatenate two arrays and returns a new array containing all elements from both input arrays. This approach can be slower due to the overhead of creating a new array and copying elements.

**Pros and Cons**

Here are some pros and cons for each approach:

* **push**:
	+ Pros: Simple, well-supported by older browsers.
	+ Cons: May be slower due to updates to the array's length.
* **spread**:
	+ Pros: Faster than `push`, more concise code.
	+ Cons: Requires support for the spread operator (`...`).
* **concat**:
	+ Pros: Can be useful when you need a new array, but may be slower.

**Other alternatives**

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

1. Using `Array.prototype.reduce()` and `Array.prototype.push()`: This approach can be more efficient than the other two methods.
2. Using `Array.prototype.concat()` with a callback function: If you need to perform an operation on each element of the concatenated array, this method may be suitable.

In summary, the benchmark measures the performance of three approaches for concatenating large arrays in JavaScript:

* `push`: Simple but potentially slower due to updates to the array's length.
* `spread` (using the spread operator `...`): Faster and more concise, but requires support for the spread operator.
* `concat`: Can be useful when creating a new array, but may be slower.

Keep in mind that browser optimizations can affect the performance of these approaches.

Related benchmarks:

push vs spread vs concat two big arrays 2 (version: 0)

Comparing performance of: push vs spread vs concat

Created: 7 years ago by: Guest

Jump to the latest result

push

spread

concat

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):