Benchmark: array update push vs spread

Script Preparation code:

var array = [].fill(0, 10, 100)
var array2 = [].fill(0, 20, 100)

Tests:

push
array.push(...array2)
spread
array = [...array, ...array2]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
spread

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 3 days ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark definition and test cases.

**What is being tested?**

MeasureThat.net is testing two approaches for updating an array: using `array.push(...array2)` and using the spread operator (`array = [...array, ...array2]`). The goal of this benchmark is to compare the performance of these two methods in updating an array with a large number of elements.

**Options being compared**

There are only two options being compared:

1. **`array.push(...array2)`**: This method uses the spread operator (`...`) to add all elements from `array2` to the end of `array`. The `push()` method is called on the resulting array.
2. **`array = [...array, ...array2]`**: This method uses the spread operator (`...`) to create a new array that combines `array` and `array2`, and then assigns it back to `array`.

**Pros and Cons of each approach**

1. **`array.push(...array2)`**:
	* Pros: Simple, easy to read, and widely supported.
	* Cons: Can be slower than the spread operator approach due to the overhead of creating a new array in push mode.
2. **`array = [...array, ...array2]`**:
	* Pros: Creates a new array with improved performance compared to `push()` mode, and is generally faster.
	* Cons: Requires understanding of the spread operator syntax and can be less readable.

**Library usage**

There is no library being used in this benchmark. The test cases only involve JavaScript core functionality.

**Special JS feature or syntax**

The use of the spread operator (`...`) is a special JavaScript feature introduced in ECMAScript 2015 (ES6). It allows for creating new arrays by spreading elements from existing arrays.

**Other alternatives**

Before adopting either approach, it's worth noting that other methods could be used to update an array:

1. **`array.concat(array2)`**: This method creates a new array and concatenates `array` and `array2`. While not as efficient as the spread operator or push mode, it is still widely supported.
2. **`Array.prototype.splice()`**: This method updates `array` in place by replacing a portion of its elements with elements from `array2`.

The choice of approach ultimately depends on the specific use case and personal preference.

Keep in mind that this benchmark only tests performance, not code readability or maintainability. Depending on the context, other factors might be more important when choosing an array update method.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36 OPR/73.0.3856.329

Browser/OS: Opera 73 on Windows

View result in a separate tab

Test name	Executions per second
push	4872102.0 Ops/sec
spread	2852154.0 Ops/sec

Related benchmarks:

array update push vs spread (version: 0)

Comparing performance of: push vs spread

Created: 3 years ago by: Guest

Jump to the latest result

push

spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 3 days ago):