Benchmark: reverse string test

Script Preparation code:

function* backwards(iterable) {
    for (let {
            length
        } = iterable; length--;) yield iterable[length]
}
function reducer(a,b) {
return a+b
}
let string = '1234567890'.repeat(60)

Tests:

backwards reduce
for(let i = 300; i--;)var abc = backwards(string).reduce(reducer)
array.from
for(let i = 300; i--;)var abc = Array.from(string).toReversed().join('')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
backwards reduce
array.from

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 23 hours ago)

User agent: Mozilla/5.0 (X11; CrOS x86_64 14541.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Chrome OS 14541.0.0

View result in a separate tab

Test name	Executions per second
backwards reduce	104.6 Ops/sec
array.from	181.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 19 hours ago):

LLMs can make mistakes. Check important info.

In the provided benchmark definition for “reverse string test,” two different approaches are compared for reversing a long string. The key points about each benchmark, including their respective pros and cons, as well as the libraries and features involved, are outlined below.

### Benchmark Approaches

1. **Backwards Reduce**:
   ```javascript
   for(let i = 300; i--;) var abc = backwards(string).reduce(reducer)
   ```
   - **Description**: This benchmark uses a generator function `backwards` that reverses a string by yielding its characters in reverse order. It then combines these characters into a final string using the `reduce` method.
   - **Pros**:
     - This approach allows for a memory-efficient way of processing large strings because it generates characters on-the-fly without creating an intermediate array of reversed characters.
     - The use of generators can lead to better performance when handling large datasets, as they only compute values as needed.
   - **Cons**:
     - Using a combination of generator functions and `reduce` might involve overhead in terms of function calls and context switching, which can reduce performance in tight loops or high-frequency function calls.
     - This method could be less readable for those unfamiliar with generator functions and the `reduce` method.

2. **Array.from**:
   ```javascript
   for(let i = 300; i--;) var abc = Array.from(string).toReversed().join('')
   ```
   - **Description**: This benchmark directly converts the string into an array using `Array.from()`, then utilizes the `toReversed()` method, followed by `join('')` to concatenate the reversed elements into a string.
   - **Pros**:
     - This method is straightforward and easy to understand, making it accessible for developers who may not be familiar with more complex constructs like generators.
     - The use of `toReversed()` (a modern JavaScript feature) provides a clear and efficient way to obtain a reversed array from the string.
   - **Cons**:
     - The `Array.from()` method creates an entire array in memory, which can be less memory-efficient, especially with large strings, as it requires additional space to store the intermediate array.
     - The need to create a new array and then reverse it may lead to slower performance compared to the generator approach in scenarios involving large inputs.

### Libraries and Features

- **Generator Functions**: The `backwards` function is a generator, which is a special type of function that can be paused and resumed, allowing it to yield values dynamically. This facilitates the creation of iterators, making it ideal for working with large datasets without consuming too much memory.
- **Array.from()**: This built-in method is used to create a new `Array` instance from an array-like or iterable object. It simplifies the conversion process but may carry overhead when dealing with significant data sizes.
- **toReversed()**: This ES2022 feature allows for a direct and efficient method to reverse arrays. The introduction of methods like this makes operations on arrays more expressive and less error-prone.

### Other Considerations and Alternatives

- **Performance Results**: The benchmark results indicate that `Array.from` significantly outperforms `backwards reduce` in this specific test case, executing approximately 180.98 operations per second versus 104.57 for the generator-based approach. This suggests that, for this use case, the direct manipulation of the string using array methods is more efficient.
  
- **Alternatives**: 
  - Other approaches could include using a simple loop to build the reversed string manually, which might not utilize higher-order functions but could yield competitive performance in specific cases.
  - Utilization of regex or specialized libraries for string manipulation (though potentially over-engineered for this problem) could serve as alternatives, depending on the complexity of the task.
  
In conclusion, the choice of method for reversing a string in JavaScript depends on the specific context and requirements. While the generator approach offers memory efficiency, the array-based approach provides better performance and clarity for typical use cases. Software engineers must weigh these factors to choose the right solution for their specific programming challenges.

Related benchmarks:

reverse string test (version: 1)

Comparing performance of: backwards reduce vs array.from

Created: 23 hours ago by: Guest

Jump to the latest result

backwards reduce

array.from

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 19 hours ago):