Benchmark: Add a property to an array using Array.push vs spread (...) operator (fixed)

Script Preparation code:

window.existingArray = ['1','2','3','4','5'];

Tests:

Adding a string using Array.push
existingArray.push('6'); existingArray.pop();
Adding a string using spread
window.existingArray = [...existingArray, '6']; existingArray.pop();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Adding a string using Array.push
Adding a string using spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Linux; Android 11; Mi A3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 106 on Android

View result in a separate tab

Test name	Executions per second
Adding a string using Array.push	781953.4 Ops/sec
Adding a string using spread	427667.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark measures the performance difference between two approaches to add a property to an array:

1. Using `Array.push()`
2. Using the spread operator (`...`)

**Options Compared**

Two options are compared:

* Option 1: Using `Array.push()` to add a new element to the end of the array.
* Option 2: Using the spread operator (`...`) to create a new array with the original elements and the newly added element.

**Pros and Cons of Each Approach**

* **Option 1 (Array.push())**
	+ Pros:
		- Efficient use of memory, as it only adds the new element to the existing array.
		- Often faster, since it doesn't create a new array object.
	+ Cons:
		- Can be slower than the spread operator for very large arrays, due to the overhead of incrementing the length property.
* **Option 2 (Spread Operator)**
	+ Pros:
		- Creates a new array object with the original elements and the newly added element, which can be faster for large arrays.
		- Can be more readable and maintainable, as it clearly expresses the intent of creating a new array.
	+ Cons:
		- Uses more memory, since it creates a new array object.
		- Can be slower than `Array.push()` for very small arrays, due to the overhead of creating a new array.

**Library Used**

The benchmark uses the `existingArray` variable, which is defined in the script preparation code. The `existingArray` is an array of strings initialized with five elements: `'1'`, `'2'`, `'3'`, `'4'`, and `'5'`. This array is used as the input for both benchmarking scenarios.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax being tested in this benchmark. It's a straightforward comparison of two simple programming approaches.

**Other Alternatives**

While not explicitly mentioned in the benchmark, other alternatives to compare might include:

* Using `Array.prototype.concat()` to concatenate the original array with the new element.
* Using a library like Lodash's `assignIn` method to add properties to an object (not applicable here, since we're working with arrays).

Keep in mind that this benchmark is intended to measure performance differences between two specific approaches, rather than exploring all possible ways to add elements to an array.

Related benchmarks:

Add a property to an array using Array.push vs spread (...) operator (fixed) (version: 0)

Add a property to an array using Array.push vs spread (...) operator

Comparing performance of: Adding a string using Array.push vs Adding a string using spread

Created: 2 years ago by: Guest

Jump to the latest result

Adding a string using Array.push

Adding a string using spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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