Benchmark: reduce vs filter

Script Preparation code:

var values = Array(1000).fill(['dupa', 'dupa2']).flat()

Tests:

reduce
values.reduce((prev, status) => prev + +(status === 'dupa'), 0)
filter
values.filter(status => status === 'dupa').length

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
filter

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Definition**

The benchmark is comparing two approaches: `reduce` and `filter`. The `reduce` function is used to apply a reduction operation to an array, while the `filter` method returns a new array with all elements that pass a test implemented by a user-provided function.

**Options Compared**

In this case, we have:

*   **Reduce**: This approach accumulates the sum of all elements in the array. It's useful when you need to process data in parallel and need an aggregate result.
*   **Filter**: This approach returns a new array with only the elements that pass a test. It's useful when you need to filter out unwanted data.

**Pros and Cons**

*   **Reduce**: Pros:
    *   Efficient for large arrays, as it avoids creating intermediate arrays.
    *   Can be used for aggregate operations (e.g., sum, max, min).
    Cons:
    *   Requires the accumulator function to handle edge cases.
    *   Less readable than filter for simple filtering use cases.
*   **Filter**: Pros:
    *   Easy to read and maintain, especially for simple filtering.
    *   Does not require handling edge cases explicitly.
    Cons:
    *   Creates a new array, which can be memory-intensive.
    *   Can be slower than reduce for large arrays.

**Library Used**

There is no specific library used in this benchmark. However, it's worth noting that some JavaScript engines may optimize certain functions or methods differently depending on the presence of specific libraries or modules.

**Special JS Feature/Syntax**

This benchmark does not use any special JavaScript features or syntax beyond the standard `reduce` and `filter` methods. It's designed to be a basic comparison of these two common array operations.

**Other Alternatives**

For large-scale performance comparisons, you can also consider using:

*   **Array.prototype.forEach()**: Similar to filter but does not return anything.
*   **Array.prototype.map()**: Returns a new array with the results of applying a provided function on every element in this array.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36

Browser/OS: Chrome 90 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
reduce	191688.0 Ops/sec
filter	91224.5 Ops/sec

Related benchmarks:

reduce vs filter (version: 0)

Comparing performance of: reduce vs filter

Created: 3 years ago by: Guest

Jump to the latest result

reduce

filter

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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