Benchmark: Space numbers every 3 digits

Tests:

Using map+reverse+join
"112345678".split("").reverse().map((x,i)=>{ if((i + 1) % 3 === 0){ return " "+x; } else { return x; } }).reverse().join("");
Using reduce
"12345678" .split("") .reverse() .reduce((acc, cur, i) => (((i + 1) % 3 === 0 ? ' ' : '') + cur + acc) , "").trim();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using map+reverse+join
Using reduce

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**
The benchmark is defined by a JSON object that provides some basic information about the test, such as its name and description (which is empty in this case). The script preparation code and HTML preparation code are also specified, but they are both null, which means that no specific setup or page is needed to run the test.

**Individual Test Cases**
The benchmark consists of two test cases:

1. **Using map+reverse+join**

In this test case, a string `112345678` is split into an array using the `split()` method. The array is then reversed and each element is processed using a callback function that checks if its index plus one is a multiple of three (i.e., if it's a position where a space should be inserted). If so, the callback returns a string with a space followed by the current element; otherwise, it returns the current element. The resulting array is then reversed again and joined back into a string using the `join()` method.

2. **Using reduce**

This test case uses the same input string `12345678`. It splits the string into an array, reverses it, and applies a reduction operation to combine the elements. The reduction function takes three arguments: the accumulator (`acc`), the current element (`cur`), and its index (`i`). It returns a string that includes a space if the index plus one is a multiple of three; otherwise, it just concatenates `cur` with `acc`. The final result is trimmed to remove any leading or trailing whitespace.

**Library: Array.prototype.map() and Array.prototype.reverse()**
These methods are built-in JavaScript methods that can be used to process arrays. They are commonly used in various programming tasks, including data processing, filtering, and manipulating collections of elements.

**Special JS Feature/Syntax: None**
There's no special JavaScript feature or syntax used in these test cases. It's purely functional programming.

**Options Compared**
In this benchmark, two different approaches to processing the string are compared:

* **Using map+reverse+join**: This approach involves splitting the string into an array, reversing it, processing each element with a callback function, and then joining the resulting elements back into a string.
* **Using reduce**: This approach uses a single reduction operation to combine the elements of the reversed array, inserting spaces at specific positions.

**Pros and Cons**

1.  **Using map+reverse+join**
    *   Pros:
        *   Easy to understand for developers familiar with callback functions.
        *   Allows for explicit control over each element's processing using a callback function.
    *   Cons:
        *   Requires more iterations (three: split, reverse, and join) compared to the reduce approach.
        *   May be less efficient due to the overhead of creating an intermediate array.

2.  **Using reduce**
    *   Pros:
        *   Single pass through the array reduces memory allocation and copying.
        *   More efficient for large inputs since it uses a single iteration over the array.
    *   Cons:
        *   May be harder to understand or debug for developers unfamiliar with reduction functions.

**Other Considerations**

*   In JavaScript, `split()` returns an empty string as its first element when dealing with strings that contain only whitespace. Therefore, it's essential to consider how this might affect the performance of these benchmarks.
*   When working with large inputs, the choice between these two approaches may become more significant due to differences in memory allocation and copying.

**Alternatives**

If there were other ways to process the input string (e.g., using regular expressions or a different data structure), alternative benchmarking methods could be employed. However, given the specific nature of this problem (splitting a string into an array, processing each element, and then joining them back together), these two approaches represent a fundamental trade-off in terms of complexity, performance, and readability.

In general, when dealing with strings or arrays in JavaScript, developers can use various built-in methods to manipulate data efficiently. However, the choice between different approaches depends on the specific requirements of the task at hand, including factors such as performance, readability, and maintainability.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0

Browser/OS: Firefox 62 on Linux

View result in a separate tab

Test name	Executions per second
Using map+reverse+join	2014521.6 Ops/sec
Using reduce	2545425.0 Ops/sec

Related benchmarks:

Space numbers every 3 digits (version: 0)

Comparing performance of: Using map+reverse+join vs Using reduce

Created: 6 years ago by: Guest

Jump to the latest result

Using map+reverse+join

Using reduce

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):