Benchmark: .flatMap() vs .map()

Script Preparation code:

var arr = [];
var i = 0;

while (i <= 1E5) arr[i] = i++;

Tests:

map().flat()
arr.map(x => x)
flatMap()
arr.flatMap(x => x)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map().flat()
flatMap()

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark definition and test cases.

**Benchmark Definition Explanation**

The benchmark tests two different approaches for flattening an array in JavaScript: `map()` with `.flat()` and `flatMap()`. The benchmark aims to compare the performance of these two methods.

**Options Compared**

Two options are compared:

1. `map()` followed by `.flat()`
2. `flatMap()`

**Pros and Cons of Each Approach**

1. **`map()` followed by `.flat()`**
	* Pros:
		+ Wide browser support (since `.flat()` was introduced in ECMAScript 2019)
		+ Easy to understand and implement
	* Cons:
		+ Requires two function calls, which can be slower than a single function call
2. **`flatMap()`**
	* Pros:
		+ Single function call, making it potentially faster
		+ Less code to write and maintain
	* Cons:
		+ Not all browsers support `flatMap()`, especially older versions

**Library and Purpose**

There is no specific library used in this benchmark. The `map()` and `flatMap()` functions are built-in JavaScript methods.

**Special JS Feature or Syntax**

`flatMap()` is a relatively new method introduced in ECMAScript 2019, which replaces the `reduce()` function with a simpler way to flatten arrays while preserving the original array structure. This syntax allows for concise and expressive code.

**Other Alternatives**

If you want to avoid using built-in methods like `map()` and `flatMap()`, you can use loops or other libraries to achieve the same result. Some alternatives include:

* Using `forEach()` with an arrow function
* Creating a new array using the spread operator (`[...array]`)
* Using a library like Lodash, which provides a `flatten()` method

Keep in mind that these alternatives might not be as efficient or readable as using built-in methods.

**Benchmark Preparation Code Explanation**

The script preparation code generates an array of 100,000 elements and assigns each element a value from 0 to 99,999. This creates a large array that can be used to test the performance of `map()` and `flatMap()`.

Related benchmarks:

.flatMap() vs .map() (version: 0)

flatMap vs map flat

Comparing performance of: map().flat() vs flatMap()

Created: 2 years ago by: Guest

Jump to the latest result

map().flat()

flatMap()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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