Benchmark: reduce + concat() vs flat()

Script Preparation code:

var params = [[ 1, 2 ], [ "hello", true, 7 ]];

Tests:

reduce
var other = params.reduce((acc, val) => acc.concat(val), []);
flat
var other = params.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:

No previous run results

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand what's being tested in this JavaScript benchmark.

**What's being tested?**

The benchmark is comparing the performance of two approaches: using `reduce()` with `Array.prototype.concat()` and using `flat()` to flatten an array.

**Options compared:**

1. **`reduce()` with `Array.prototype.concat()`:**
This approach uses the `reduce()` method to iterate over the input arrays, concatenating each element to an accumulator array. The `concat()` method is called on each iteration to add new elements to the accumulator.
2. **`flat()`:** This is a modern JavaScript method introduced in ECMAScript 2019 (ES9). It flattens an array of arrays into a single-level array.

**Pros and Cons:**

1. **`reduce()` with `Array.prototype.concat()`:**
	* Pros:
		+ Widely supported across older browsers.
		+ Easy to implement if you're familiar with the `reduce()` method.
	* Cons:
		+ Requires explicit concatenation using `concat()`, which can lead to performance overhead.
2. **`flat()`:**
	* Pros:
		+ Modern and efficient, using a native method that's implemented in V8 (Google's JavaScript engine).
		+ Simplifies code and eliminates the need for manual concatenation.
	* Cons:
		+ May not work as expected in older browsers or environments without ES9 support.

**Library/Utility:**

There is no explicit library mentioned, but `Array.prototype.reduce()` and `Array.prototype.flat()` are built-in methods provided by modern JavaScript engines.

**Special JS feature/syntax:**

The benchmark uses the modern `flat()` method, which requires JavaScript to be compiled with ES9 support (or later). This means that older browsers or environments without ES9 support will not execute this test case correctly.

**Benchmark preparation code and individual test cases:**

The preparation code defines an array of arrays (`params`) used as input for the benchmark. Each test case uses a different approach to process `params`, either using `reduce()` with `concat()` or directly calling `flat()`. The individual test cases are represented by two examples:

* `reduce`: Uses `reduce()` with `Array.prototype.concat()`.
* `flat`: Directly calls `Array.prototype.flat()`.

**Latest benchmark result:**

The results show the performance of each approach on a Chrome 87 browser running on a Mac OS X 10.14.6 environment, measured in executions per second. The first test case (`reduce`) outperforms the second test case (`flat`), but not significantly so.

**Other alternatives:**

If you prefer an older approach or want to support even more browsers, you could consider using:

* `Array.prototype.slice()` and `Array.prototype.concat()`: This approach uses explicit slicing and concatenation to achieve a similar result.
* `reduce()` with `Array.prototype.push()`: Another variation of the original approach, using `push()` instead of `concat()`.

Keep in mind that these alternatives may have different performance characteristics or require additional code to implement correctly.

Related benchmarks:

reduce + concat() vs flat() (version: 0)

reduce + Array.prototype.concat vs Array.prototype.flat

Comparing performance of: reduce vs flat

Created: 5 years ago by: Guest

Jump to the latest result

reduce

flat

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):