Benchmark: JavaScript reverse vs toReversed [1000 elements of strings]

Script Preparation code:

array = [];
for (let i = 0; i  < 1000; i++) { array.push(btoa(Math.random().toString()).substring(10,15)); }

Tests:

Array.reverse()
array.reverse();
Array.toReversed()
array.toReversed();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.reverse()
Array.toReversed()

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser/OS: Chrome 127 on Linux

View result in a separate tab

Test name	Executions per second
Array.reverse()	549972.5 Ops/sec
Array.toReversed()	801455.9 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark is designed to compare the performance of two JavaScript methods: `Array.reverse()` and `Array.toReversed()`. The test creates an array with 1000 elements, where each element is a string created using `btoa` (binary-to-text encoding) with a random string. This helps distribute the workload evenly across the array.

**Options Compared**

The two options being compared are:

1. **`Array.reverse()`**: Reverses the order of the elements in the array.
2. **`Array.toReversed()`**: Not a standard JavaScript method, but rather a custom implementation using `Array.prototype.map()`, which returns a new array with the same elements in reversed order.

**Pros and Cons**

* **`Array.reverse()`**:
	+ Pros: It's a widely supported, built-in method that can be easily implemented.
	+ Cons: It modifies the original array, can be slower for large datasets due to the overhead of reversing the entire array.
* **`Array.toReversed()`**:
	+ Pros: It creates a new reversed array without modifying the original one, which might be beneficial for preserving data integrity.
	+ Cons: It's not a standard method and may not be supported by all browsers or environments.

**Other Considerations**

When testing performance, it's essential to consider factors like:

* Cache behavior: How does each method affect cache hits/misses?
* Loop unrolling: Can the methods be optimized for loop unrolling or other optimization techniques?

**Library Usage**

In this benchmark, `btoa` is used to create random strings. `btoa` is a binary-to-text encoding function that converts binary data into a text representation. Its purpose is to encode binary data (like images) as text.

**Special JS Feature or Syntax**

There's no special JavaScript feature or syntax being tested in this benchmark. The focus is on the performance comparison between two methods.

Now, regarding alternatives:

* **Other approaches for reversing an array**: Instead of using `Array.reverse()` or `Array.toReversed()`, you could use other algorithms like:
	+ Iterative approach with a loop that swaps elements from both ends.
	+ Using a queue data structure to store the elements in reverse order.
* **Alternative methods for creating reversed arrays**:
	+ Use `Array.prototype.map()` and `String.prototype.split()`/`String.prototype.slice()` to create a new reversed array.

These alternatives can be explored to see if they offer better performance or more efficient ways to achieve the same result.

Related benchmarks:

JavaScript reverse vs toReversed [1000 elements of strings] (version: 0)

Compare Array.reverse() to Array.toReversed() performance wise.

Comparing performance of: Array.reverse() vs Array.toReversed()

Created: one year ago by: Registered User

Jump to the latest result

Array.reverse()

Array.toReversed()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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