Benchmark: Spread Operator VS Array.slice()

Tests:

Spread Operation
const words = [ 'apple', 'banana', 'orange', 'grape', 'kiwi', 'peach', 'strawberry', 'blueberry', 'pineapple', 'watermelon', 'carrot', 'broccoli', 'tomato', 'cucumber', 'potato', 'elephant', 'lion', 'giraffe', 'zebra', 'monkey' ]; const newWords = [...words];
Array.slice()
const words = [ 'apple', 'banana', 'orange', 'grape', 'kiwi', 'peach', 'strawberry', 'blueberry', 'pineapple', 'watermelon', 'carrot', 'broccoli', 'tomato', 'cucumber', 'potato', 'elephant', 'lion', 'giraffe', 'zebra', 'monkey' ]; const newWords = words.slice();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread Operation
Array.slice()

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
Spread Operation	139385040.0 Ops/sec
Array.slice()	238615360.0 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 explanation of the provided benchmark.

**Benchmark Definition and Purpose**
The benchmark is designed to compare the performance of two approaches: using the spread operator (`...`) and `Array.slice()` methods to create a copy of an array in JavaScript.

**Options Compared**

1. **Spread Operator (`...`)**: This method creates a new array by spreading the elements of the original array into a new array.
2. **`Array.slice()`**: This method returns a shallow copy of a portion of an array, starting from the specified index and ending at the specified length.

**Pros and Cons**

* **Spread Operator (`...`)**
	+ Pros:
		- More intuitive and readable code
		- Can be more efficient for small arrays due to its nature (it doesn't create a new object or array, but rather a reference to the original elements)
	+ Cons:
		- May have performance issues when dealing with large arrays (as it requires creating a new array)
* **`Array.slice()`**
	+ Pros:
		- More efficient for large arrays as it creates a shallow copy of a portion of the original array
	+ Cons:
		- Less intuitive and less readable code

**Library/Function Used**

None. This benchmark only uses built-in JavaScript functions.

**Special JS Feature/Syntax (none)**

No special JavaScript features or syntax are used in this benchmark.

**Other Alternatives**

If you want to create a copy of an array, there are other alternatives:

1. **`Array.prototype.map()`**: You can use `map()` on the original array and then spread the result into a new array using the spread operator (`...`). This method creates a new array with the same length as the original array.
2. **`Array.from()`**: Similar to `map()`, you can use `from()` to create an array from an iterable object, such as an array.

**Benchmark Results**

The benchmark results show that:

* The spread operator (`...`) is slightly faster than `Array.slice()` on this specific test case.
* However, it's essential to note that the performance difference between these two methods may not be significant for all use cases and JavaScript engines. Additionally, if you're working with large arrays, `Array.slice()` might be a better choice due to its efficiency.

In summary, when deciding between using the spread operator (`...`) or `Array.slice()`, consider the size of your array, readability requirements, and performance constraints.

Related benchmarks:

Spread Operator VS Array.slice() (version: 0)

performance test!

Comparing performance of: Spread Operation vs Array.slice()

Created: 2 years ago by: Guest

Jump to the latest result

Spread Operation

Array.slice()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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