Benchmark: Stelian - MeasureThat.net

Script Preparation code:

var arr = Array(10_000).fill(0)

Tests:

Reduce
arr.reduce((acc, x) => {acc.push(x); acc.push(x); return acc}, [])
FlatMap
arr.flatMap(x => [x, x])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce
FlatMap

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 27 days ago):

LLMs can make mistakes. Check important info.

This benchmark compares two ways to double each element in an array of 10,000 zeroes:

**Option 1: `reduce`**

```javascript
arr.reduce((acc, x) => { acc.push(x); acc.push(x); return acc }, [])
```

- **Explanation:**  The `reduce()` method iterates through the array and accumulates results in a new array (`acc`). For each element (`x`), it pushes `x` twice into the accumulator, effectively doubling each value. 
- **Pros:** Clear syntax, conceptually simple to understand. 
- **Cons:** Can be less efficient than other methods due to repeated pushing operations within the callback.

**Option 2: `flatMap`**

```javascript
arr.flatMap(x => [x, x])
```

- **Explanation:** The `flatMap()` method iterates through the array and applies a transformation function (`x => [x, x]`) to each element. This function returns an array containing the original element twice. 
  `flatMap()` then flattens these nested arrays into a single new array.
- **Pros:** More concise syntax, potentially more efficient than `reduce` due to flattening being handled internally.
- **Cons:** Might be less familiar to developers who are newer to JavaScript.

**Other Considerations:**

* **Library Usage:** No external libraries are used in these benchmarks.
* **Special JS Features:**  This benchmark utilizes standard JavaScript array methods (`reduce`, `flatMap`).

**Alternatives:**

1. **`map()` followed by `concat()`:** You could map over the array to double each element and then use `concat()` to combine the results into a single array. This approach might be slightly less efficient than `flatMap`.

2. **For Loop:** A traditional for loop could also achieve this, but it's generally considered less concise and potentially less performant compared to the array methods.

Let me know if you have any more questions!

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser/OS: Chrome 97 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Reduce	8801.7 Ops/sec
FlatMap	341.7 Ops/sec

Related benchmarks:

Stelian (version: 0)

Comparing performance of: Reduce vs FlatMap

Created: 2 years ago by: Guest

Jump to the latest result

Reduce

FlatMap

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 27 days ago):