Benchmark: flat vs flatMap vs reduce

Script Preparation code:

var arr = Array(10_000).fill(Array(20).fill(Math.random()*50))

Tests:

reduce
arr.reduce((acc, val) => acc.concat(val), []);
flatMap
arr.flatMap(x => x)
flat
arr.flat()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
reduce
flatMap
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/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
reduce	1.2 Ops/sec
flatMap	78.2 Ops/sec
flat	78.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**Benchmark Overview**

The provided JSON represents a benchmark test case on MeasureThat.net, which compares the performance of three different approaches for flattening an array:

1. `flat()`
2. `flatMap(x => x)`
3. `reduce((acc, val) => acc.concat(val), [])`

These approaches are compared in terms of their execution speed, measured in executions per second.

**Options Compared**

Here's a brief explanation of each option:

1. **`flat()`**: This method flattens an array by recursively calling itself on each element. It's a simple and efficient way to flatten an array.
2. **`flatMap(x => x)`**: This is a more modern approach that uses the `flatMap()` method, which is similar to `map()`, but returns an iterator instead of an array. The callback function `x => x` simply returns each element as is.
3. **`reduce((acc, val) => acc.concat(val), [])`**: This approach uses the `reduce()` method to iterate over the array and concatenate its elements into a single array.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **`flat()`**:
	* Pros: Fast, simple, and efficient.
	* Cons: May cause stack overflow errors for very large arrays due to recursion.
2. **`flatMap(x => x)`**:
	* Pros: Modern, concise, and relatively fast.
	* Cons: Requires a modern browser or JavaScript engine that supports `flatMap()`.
3. **`reduce((acc, val) => acc.concat(val), [])`**:
	* Pros: Flexible, can be used for other reduction operations, and works in older browsers.
	* Cons: May be slower than the first two options due to the overhead of concatenating arrays.

**Library Usage**

None of the provided benchmarks use any external libraries.

**Special JavaScript Features or Syntax**

None of the provided benchmarks utilize special JavaScript features or syntax, such as async/await or generator functions.

**Other Alternatives**

If you'd like to explore alternative approaches for flattening an array, here are a few options:

1. **`concat()`**: This method concatenates two arrays and returns the result.
2. **`slice()`**: This method extracts a portion of an array.
3. **`forEach()`**: This method executes a callback function on each element of an array.

Keep in mind that these alternatives may have different performance characteristics compared to the `flat()`, `flatMap()`, and `reduce()` methods.

Related benchmarks:

flat vs flatMap vs reduce (version: 0)

Comparing performance of: reduce vs flatMap vs flat

Created: 2 years ago by: Guest

Jump to the latest result

reduce

flatMap

flat

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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