Benchmark: flatten reduce vs for

Script Preparation code:

var a = [[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]

Tests:

for
const result = []; for (const item of a) result.push(...item);
reduce
const result = a.reduce((flat, el) => [...flat, ...el], []);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.106 Safari/537.36

Browser/OS: Chrome 91 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
for	4827038.0 Ops/sec
reduce	3095272.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches to flatten an array of arrays: using `for` loop and using `Array.prototype.reduce()` method.

**Approaches Compared**

1. **For Loop**: This approach uses a traditional `for` loop to iterate over each inner array and push its elements into a result array.
2. **Reduce Method**: This approach uses the `reduce()` method of the `Array` prototype, which applies a callback function to each element in the array, accumulating a value that is returned as the final output.

**Pros and Cons**

* **For Loop**:
	+ Pros: Easy to understand and implement, works well for small arrays.
	+ Cons: Can be slower than `reduce()` for large arrays due to the overhead of the loop control flow and potential array concatenation issues.
* **Reduce Method**:
	+ Pros: More concise and efficient, especially for large arrays, as it avoids unnecessary array concatenations.
	+ Cons: May have a higher learning curve due to its functional programming nature.

**Other Considerations**

* Both approaches assume that the inner arrays are not nested too deeply. If they were, a more complex solution might be needed.
* The `reduce()` method requires an initial value for the accumulator, which in this case is initialized as an empty array (`[]`).

**Library and Special Features**

There is no external library used in these benchmarks.

No special JavaScript features or syntax are being tested here. Both approaches use only standard JavaScript features.

**Alternatives**

If you need to flatten arrays of arrays, other approaches you might consider include:

* Using `Array.prototype.forEach()` method with a callback function
* Using `Array.prototype.map()` method (although it would return an array of arrays instead of a single array)
* Using a library like Lodash's `flatten` function

Keep in mind that the choice of approach depends on your specific use case, performance requirements, and personal preference.

Related benchmarks:

flatten reduce vs for (version: 0)

Comparing performance of: for vs reduce

Created: 3 years ago by: Guest

Jump to the latest result

for

reduce

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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