Benchmark: Flat vs Reduce - MeasureThat.net

Tests:

Reduce
const a = [[1,2,3],[1,2,3]] a.reduce((acc, curr) => { acc.push(...curr) return acc },[])
Flat
const a = [[1,2,3],[1,2,3]] a.flat()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce
Flat

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36 Edg/139.0.0.0

Browser/OS: Chrome 139 on Windows

View result in a separate tab

Test name	Executions per second
Reduce	28800740.0 Ops/sec
Flat	14239346.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is being tested?**

The provided benchmark tests two different approaches to flatten an array of arrays in JavaScript:

1. **`reduce()` method**: The first test case uses the `reduce()` method to flatten the array of arrays.
2. **`flat()` method**: The second test case uses the `flat()` method to flatten the array of arrays.

**Options compared**

The two methods being tested are alternatives for achieving the same goal: flattening an array of arrays into a single, one-dimensional array. The main difference between them lies in their behavior and usage:

* **`reduce()` method**: This method applies a reducer function to each element in the array of arrays, accumulating the result in an accumulator variable. In this case, the reducer function simply pushes all elements from the current inner array onto the accumulator.
* **`flat()` method**: This method returns a new, shallow copy of the original array, with all sub-arrays flattened into single elements.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **`reduce()` method**:
	+ Pros: more flexible, allows for arbitrary reduction logic.
	+ Cons: slower than `flat()`, requires explicit loop or recursive function.
* **`flat()` method**:
	+ Pros: faster, more concise, and easier to read.
	+ Cons: only flattens arrays one level deep, may not be suitable for all use cases.

**Library usage**

Neither of the test cases uses any external libraries. The `reduce()` method is a built-in JavaScript function, while the `flat()` method was introduced in ECMAScript 2019 (ES11).

**Special JS feature or syntax**

There are no special features or syntax used in these test cases.

**Alternative approaches**

If you want to flatten an array of arrays, here are some alternative approaches:

* **Using `forEach` and `push`**: You can use the `forEach` method to iterate over each inner array and push all elements onto a single accumulator array.
* **Using a `for...of` loop**: You can use a `for...of` loop to iterate over each inner array and push all elements onto a single accumulator array.
* **Using recursion**: You can write a recursive function to flatten the array of arrays, although this approach is often less efficient than `reduce()` or `flat()`.
* **Using a third-party library**: If you need more complex flattening logic, you may want to consider using a third-party library like Lodash.

Keep in mind that these alternative approaches might have different performance characteristics and readability trade-offs compared to the `reduce()` and `flat()` methods.

Related benchmarks:

Flat vs Reduce (version: 0)

Comparing performance of: Reduce vs Flat

Created: 3 years ago by: Guest

Jump to the latest result

Reduce

Flat

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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