Benchmark: Javascript Array Spread vs Push

Script Preparation code:

var array = [];
var newElement = "Hello";

Tests:

Push
array.push(newElement);
Spread
array = [...array, newElement];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Push
Spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Push	6981545.5 Ops/sec
Spread	4.6 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's being tested in this specific benchmark.

**Benchmark Definition**

The benchmark is testing two different ways to add an element to an array: using the `push()` method versus using array spread syntax (`[...array, newElement]`). The script preparation code initializes an empty array `var array = []` and defines a variable `newElement` with the value `"Hello"`.

**Options Being Compared**

There are two options being compared:

1. **Push**: Using the `push()` method to add an element to the end of the array.
2. **Spread**: Using array spread syntax (`[...array, newElement]`) to create a new array with the original elements and the added element.

**Pros and Cons**

* **Push Method**:
	+ Pros: Fast and efficient, as it only modifies the existing array and doesn't create a new one.
	+ Cons: May not be suitable for large arrays or when you need to preserve the original array's length.
* **Array Spread Syntax**:
	+ Pros: Allows for creating a new array with the desired elements, which can be useful in certain situations (e.g., when working with immutable data structures).
	+ Cons: Creates a new array, which can lead to increased memory usage and performance overhead.

**Library Usage**

There is no explicit library mentioned in the benchmark definition. However, it's likely that the `push()` method is implemented by the JavaScript engine itself or by the browser's built-in array implementation.

**Special JS Feature/Syntax**

The benchmark uses the spread syntax (`[...array, newElement]`), which is a relatively modern feature introduced in ECMAScript 2015 (ES6). It allows for creating new arrays using the spread operator, making it easier to work with arrays and other data structures. Other alternative ways of creating arrays using this syntax are also tested.

**Other Considerations**

This benchmark highlights the importance of considering performance and memory usage when working with large datasets or optimizing code for specific use cases. The results will give insight into how different approaches impact execution speed, which can be crucial in various applications, such as web development, scientific computing, or data analysis.

**Alternatives**

Other alternatives for adding elements to an array include:

* Using `Array.prototype.concat()` to create a new array with the original elements and the added element.
* Using `Array.prototype.unshift()` to add elements to the beginning of the array (note that this method modifies the original array).
* Using a custom implementation, such as using a linked list or other data structure.

Keep in mind that each alternative has its own trade-offs in terms of performance, memory usage, and complexity.

Related benchmarks:

Javascript Array Spread vs Push (version: 0)

Comparing performance of: Push vs Spread

Created: 6 years ago by: Guest

Jump to the latest result

Push

Spread

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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