Benchmark: _.flatten vs .flatMap

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Tests:

_.flatten
const arr = [['1', '2', '3'], ['1', '2', '3'], ['1', '2', '3']] _.flatten(arr)
.flat
const arr = [['1', '2', '3'], ['1', '2', '3'], ['1', '2', '3']] arr.flatMap((item) => item)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
_.flatten
.flat

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
_.flatten	8869182.0 Ops/sec
.flat	5077209.0 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 benchmark and explain what's being tested.

**What is being tested?**

The provided JSON represents two JavaScript microbenchmarks: `_flatten` and `.flatMap`. Both tests are designed to measure the performance of these two methods from the Lodash library, which provides utility functions for functional programming in JavaScript.

**Options being compared**

In this benchmark, we have two test cases:

1. `_.flatten(arr)`: This method flattens an array of arrays into a single array.
2. `arr.flatMap((item) => item)`: This is a modern ES6 syntax that achieves the same result as `.flatten()` but with a more concise and expressive way of writing it.

**Pros and Cons of each approach:**

1. `.flatten()`: This method has been around for a while and is widely supported by older browsers and Node.js versions.
	* Pros:
		+ More mature and stable implementation
		+ Works in older browsers and environments
	* Cons:
		+ May be less efficient or more verbose than the modern syntax
2. `.flatMap()`: This method is a newer addition to the JavaScript standard library, introduced in ECMAScript 2019.
	* Pros:
		+ More concise and expressive way of writing the same logic
		+ Generally faster execution time due to its native support
	* Cons:
		+ May not work in older browsers or environments that don't support ES6+
		+ Requires more knowledge of modern JavaScript syntax

**Other considerations:**

Both methods have different performance characteristics, especially when dealing with large arrays. The `.flatMap()` method is generally faster due to its native support and optimized implementation. However, the `_.flatten()` method still has its advantages in terms of stability and compatibility.

When choosing between these two methods, consider the following:

* Use `.flatMap()` if:
	+ You're targeting modern browsers or Node.js versions that support ES6+
	+ You want a more concise and expressive way of writing array flattening logic
	+ Performance is critical for your use case
* Use `_.flatten()` if:
	+ You need to support older browsers or environments
	+ You prefer a more traditional and stable implementation

**Library and its purpose:**

Lodash (also known as _.js) is a popular utility library that provides a collection of functional programming helpers, including `flatten()`. Its purpose is to simplify common tasks in JavaScript development, such as array manipulation, object iteration, and more.

In this benchmark, Lodash's `.flatten()` method is used as the baseline for comparison with the modern ES6 syntax.

Related benchmarks:

_.flatten vs .flatMap (version: 0)

Comparing performance of: _.flatten vs .flat

Created: one year ago by: Registered User

Jump to the latest result

_.flatten

.flat

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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