Benchmark: concat vs flatMap

Tests:

concat
ids = Array.from(Array(10).keys()); [].concat(...ids.map(a => [a]));
flatMap
ids = Array.from(Array(10).keys()); ids.flatMap(a => [a]);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat
flatMap

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
concat	406825.8 Ops/sec
flatMap	290253.2 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.

**Benchmark Definition**

The benchmark measures the performance difference between two approaches: `concat` and `flatMap`. These two methods are used to iterate over arrays and concatenate or flatten them, respectively.

**Options Compared**

Here, we have two main options being compared:

1. **Concatenation using Array.prototype.concat()**: This method takes an array of elements as an argument and returns a new array that is the concatenation of the original array and all the elements passed to it.
2. **Flattening using Array.prototype.flatMap()**: This method takes a function that returns an array and applies it to each element of the original array, returning a new array with the results.

**Pros and Cons**

* **Concatenation using concat():**
	+ Pros:
		- Easy to understand and implement.
		- Can be useful when working with small arrays or simple data structures.
	+ Cons:
		- Creates a new array on each iteration, leading to memory allocation overhead.
		- May perform poorly for large datasets due to the repeated allocation of memory.
* **Flattening using flatMap():**
	+ Pros:
		- More efficient than concatenation, as it avoids the need for repeated memory allocations.
		- Can handle large datasets more effectively, as it doesn't require allocating new arrays on each iteration.
	+ Cons:
		- May be less intuitive to understand and implement, especially for those without experience with functional programming concepts.

**Library/Function Used**

In this benchmark, no external library is used. The `Array.prototype.concat()` and `Array.prototype.flatMap()` methods are built-in to the JavaScript language.

No special JavaScript features or syntax are mentioned in this benchmark, so there's nothing specific to note about that aspect.

**Other Alternatives**

If you need to iterate over arrays and concatenate or flatten them, other approaches you might consider include:

* Using a loop: `for (var i = 0; i < array.length; i++) { array[i] = ... }` for concatenation, or `for (var i = 0; i < array.length; i++) { result.push(...array[i]) }` for flattening.
* Using Array.prototype.map() and then concatenating: `const flatMapResult = array.flatMap(a => [a]).concat(...)`
* Using other libraries or frameworks that provide optimized array manipulation functions, such as Lodash or Ramda.

Keep in mind that the performance differences between these approaches will depend on the specific use case, data size, and JavaScript engine being used. MeasureThat.net provides a useful platform to compare different approaches under various conditions.

Related benchmarks:

concat vs flatMap (version: 0)

Comparing performance of: concat vs flatMap

Created: 3 years ago by: Guest

Jump to the latest result

concat

flatMap

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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