Benchmark: filter + map vs reduce 1234567

Script Preparation code:

var values = []
for(i=0; i<1000; i++){ values.push([i, i]) }

Tests:

flatMap
values.flatMap(e => [e, e * 2])
reduce
values.reduce((acc, x) => { acc.concat([i, i * 2]); return acc; }, [])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
flatMap
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

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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 JSON represents two individual test cases, comparing the performance of two different approaches:

1. `flatMap`: Using the `flatMap()` method to transform an array of arrays into a single array.
2. `reduce`: Using the `reduce()` method to concatenate arrays.

In both cases, we're creating an array of 1000 elements, where each element is an array with two values: `[i, i]`. The test aims to measure the performance difference between these two approaches in terms of execution time and number of executions per second.

**Options compared**

The options being compared are:

* `flatMap()`: A method introduced in ECMAScript 2019 (ES10) that flattens an array of arrays into a single array.
* `reduce()` with concatenation: A method introduced in ECMAScript 1999 (ES3) that reduces an array by applying a callback function to each element.

**Pros and Cons**

Here are some pros and cons of each approach:

* **flatMap()**:
	+ Pros:
		- More concise and expressive code.
		- Can be more efficient due to the use of internal buffers.
	+ Cons:
		- Not supported in older browsers or environments (pre-ES10).
* `reduce()` with concatenation:
	+ Pros:
		- Widely supported across different browsers and environments.
		- Has been around for a long time, so its behavior is well understood.
	+ Cons:
		- Can lead to performance issues due to the overhead of concatenating arrays.

**Library**

There is no explicit library mentioned in the provided JSON. However, it's likely that MeasureThat.net uses the browser's built-in functions and engine to execute the benchmarks.

**Special JS feature or syntax**

The `flatMap()` method is a relatively new feature introduced in ECMAScript 2019 (ES10). It was added to provide a more concise way of transforming arrays. The use of template literals (`\r\n`) in some of the benchmark definitions suggests that it may also be using some modern JavaScript features.

**Other alternatives**

If `flatMap()` is not supported, an alternative approach could be to use the `map()` method and then concatenate the results using the `concat()` method or the spread operator (`...`). However, this would likely be slower than the original `reduce()` implementation with concatenation. Another option could be to use a custom loop to iterate over the array and perform the transformations manually.

In summary, MeasureThat.net is comparing the performance of two approaches:

1. Using the `flatMap()` method (ECMAScript 2019+).
2. Using the `reduce()` method with concatenation (ECMAScript 1999-).

The test results show that `flatMap()` is generally faster than the original `reduce()` implementation, especially in modern browsers and environments.

Related benchmarks:

filter + map vs reduce 1234567 (version: 0)

Comparing performance of: flatMap vs reduce

Created: 3 years ago by: Guest

Jump to the latest result

flatMap

reduce

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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