Benchmark: Reduce vs FlatMap (500 x 20)

Script Preparation code:

var ITEMS_PER_PAGE = 500
var PAGES = 20

var data = {
  "id": "11eba174-55d1-f1ed-ba25-0269c634a921",
  "firstName": "Testy",
  "lastName": "McTest",
  "jobTitle": "Tester",
  "email": "test@test.com",
  "mobilePhone": "(123) 456-7890",
  "username": "test@test.com",
  "status": "ACTIVE",
}

var page = Array.from({ length: ITEMS_PER_PAGE }).map(item => data)

var pages = Array.from({ length: PAGES }).map(item => ({ data: page }))

Tests:

Array.prototype.reduce
pages.reduce((acc, cur) => [...acc, ...cur.data], [])
Array.prototype.flatMap
pages.flatMap(item => item.data)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.prototype.reduce
Array.prototype.flatMap

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36

Browser/OS: Chrome 107 on Linux

View result in a separate tab

Test name	Executions per second
Array.prototype.reduce	4261.0 Ops/sec
Array.prototype.flatMap	489.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmarking setup and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark is designed to compare two methods: `Array.prototype.reduce` with array destructuring vs `Array.prototype.flatMap`. The test simulates a 500x20 two-dimensional array, equivalent to 20 pages each with 500 items. This setup allows for a fair comparison of the performance between these two array manipulation methods.

**Options Compared**

There are two options being compared:

1. **`Array.prototype.reduce` with array destructuring**: This method uses array destructuring (e.g., `const [a, b] = arr;`) to extract values from each element in the array.
2. **`Array.prototype.flatMap`**: This method creates a new array by flattening each element of the input array.

**Pros and Cons**

Here are some pros and cons for each approach:

### Array.prototype.reduce with Array Destructuring

Pros:

* More memory-efficient, as it avoids creating a new array
* Can be more concise and readable in certain cases
* Allows for easier handling of nested arrays

Cons:

* Requires understanding of array destructuring syntax
* May not be as intuitive or familiar to developers who haven't worked with this feature before
* Can be slower due to the additional overhead of parsing and executing array destructuring

### Array.prototype.flatMap

Pros:

* Faster execution, as it avoids the overhead of array destructuring
* More straightforward and easier to understand for developers without experience with array destructuring
* More suitable for large datasets or performance-critical code

Cons:

* Creates a new array, which can be memory-intensive for large inputs
* May not be as concise or readable in certain cases

**Other Considerations**

The benchmarking setup also considers the following factors:

* **JavaScript version**: The test is likely running on a modern JavaScript engine (e.g., V8) that supports these methods.
* **Browser and Device Platform**: The test results are from Chrome 107 on a desktop Linux machine. This might not represent other browsers or devices.

**Libraries Used**

The test case uses the `Array.prototype` method directly, which is part of the JavaScript standard library. There are no additional libraries used in this benchmarking setup.

**Special JS Features or Syntax**

No special JavaScript features or syntax are used in these methods. The array destructuring feature (e.g., `[a, b] = arr`) is a standard JavaScript syntax that has been widely adopted since ES6.

**Alternatives**

Other alternatives for manipulating arrays include:

* **`Array.prototype.map()`**: Creates a new array with the results of applying a provided function to each element.
* **`Array.prototype.filter()`**: Creates a new array with all elements that pass the test implemented by the provided function.
* **`reduce()` methods from other libraries**: Some third-party libraries (e.g., Lodash) provide additional reduce methods with different signature or behavior.

Keep in mind that these alternatives might not be directly comparable to `Array.prototype.reduce` and `Array.prototype.flatMap`, as they may have different performance characteristics, syntax, or use cases.

Related benchmarks:

Reduce vs FlatMap (500 x 20) (version: 0)

Speed comparison between Array.prototype.reduce using array destructuring vs Array.prototype.flatMap, for a 500 by 20 two-dimensional array, simulating 20 pages each with 500 items

Comparing performance of: Array.prototype.reduce vs Array.prototype.flatMap

Created: 2 years ago by: Registered User

Jump to the latest result

Array.prototype.reduce

Array.prototype.flatMap

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):