Benchmark: flatMap vs map/flat 2

Script Preparation code:

var arr = new Array(100).fill(1);

Tests:

Test flatMap
arr.flatMap((el) => el + 1);
Test map/flat
arr.map((el) => el + 1).flat();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Test flatMap
Test map/flat

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Windows

View result in a separate tab

Test name	Executions per second
Test flatMap	192507.7 Ops/sec
Test map/flat	120271.3 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided benchmark.

**Benchmark Overview**

The benchmark measures the performance difference between two approaches: `flatMap` and `map/flat`. The test case creates an array of 100 elements filled with the value `1`, then applies a transformation to each element using these two different methods.

**Options Compared**

There are two options being compared:

1. **`arr.flatMap((el) => el + 1);`**: This uses the `flatMap()` method, which is a modern JavaScript method that flattens an array of arrays into a single array.
2. **`arr.map((el) => el + 1).flat();`**: This combines two methods: `map()` and `.flat()`. The `map()` method applies the transformation to each element, while the `.flat()` method flattens the resulting array.

**Pros and Cons of Each Approach**

* **`flatMap()`**:
	+ Pros: More concise and expressive code. It's often faster than using `map()` and `.flat()`.
	+ Cons: Some older browsers or environments might not support it, as it was introduced in ECMAScript 2019.
* **`map()` and `.flat()`**:
	+ Pros: Widely supported across modern browsers and environments. They're also more explicit and easier to understand for developers who are familiar with these methods.
	+ Cons: More verbose code compared to `flatMap()`. The two-step process can be less efficient than using a single method.

**Library/Features Used**

In this benchmark, no specific JavaScript library is used beyond the built-in methods (`map()` and `.flat()`). However, it's worth noting that some browsers or environments might have additional features enabled or disabled by default, which could affect the performance of these methods.

**Special JS Features/Syntax**

The `flatMap()` method uses a modern JavaScript feature called **template literals**, which allow you to embed expressions inside string literals. This syntax is not supported in all environments and was introduced in ECMAScript 2015 (ES6).

**Other Considerations**

When choosing between these two approaches, consider the trade-offs between code readability, conciseness, and performance. If you're working with an older environment or need to ensure compatibility across different browsers, using `map()` and `.flat()` might be a safer choice.

In terms of alternatives, other approaches for flattening arrays could include:

* Using a simple loop: `arr.forEach((el) => arr.push(el + 1));`
* Using the spread operator (`[...arr].push(el + 1)`)
* Using a library like Lodash or Ramda, which provide specialized functions for array manipulation.

However, these alternatives might not be as concise or expressive as using `flatMap()` or combining `map()` and `.flat()`.

Related benchmarks:

flatMap vs map/flat 2 (version: 0)

Comparing performance of: Test flatMap vs Test map/flat

Created: one year ago by: Guest

Jump to the latest result

Test flatMap

Test map/flat

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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