Benchmark: array.forEach() vs .reduce test2

Script Preparation code:

var array = [];
for (var i = 0; i < 10000; i++) {
  array[i] = i;
}

var firstTestResults = [];
var secondTestResults = [];

Tests:

array.forEach()
array.forEach((v) => { let value = v + 10; if (value % 2 === 0) { firstTestResults.push(value); } });
array.reduce()
secondTestResults = array.reduce((acc, value) => { value = value + 10; if (value % 2 === 0) { acc.push(value); } return acc; }, []);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array.forEach()
array.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 break down the provided benchmark and explain what's being tested, compared, and considered.

**Benchmark Context**

The benchmark is designed to compare the performance of two JavaScript methods: `array.forEach()` and `array.reduce()`. Both methods are used to iterate over an array and perform some operation on each element. The goal is to determine which method is faster for this specific use case.

**What's Being Tested?**

In the provided benchmark, two test cases are being compared:

1. `array.forEach()`: This method iterates over an array using a callback function that is executed for each element in the array.
2. `array.reduce()`: This method reduces an array to a single value by applying a callback function to each element in the array.

**Comparison Options**

The benchmark compares these two methods under different scenarios:

* Both methods are used with a large array of 10,000 elements, which is sufficient for testing performance differences.
* The `array.forEach()` method uses a callback function that checks if the current value is even and adds it to an output array (`firstTestResults`) if it is. The `array.reduce()` method uses a similar logic but accumulates values in a single output array (`secondTestResults`).
* No other methods or optimization techniques are being tested.

**Pros and Cons of Each Approach**

Here's a brief analysis of the pros and cons of each approach:

* **array.forEach()**:
	+ Pros: Easy to implement, intuitive syntax, and suitable for iterating over arrays.
	+ Cons: May be less efficient than `array.reduce()` due to the overhead of creating and executing multiple callback functions.
* **array.reduce()**:
	+ Pros: Can accumulate values in a single output array, reducing memory allocations and copies.
	+ Cons: Requires more knowledge of the method's syntax and limitations (e.g., initial value for accumulator).

**Library Usage**

The benchmark uses the `console` object to print results, which is a built-in JavaScript library.

**Special JS Feature/Syntax**

There are no special JS features or syntax being used in this benchmark. The code adheres to standard JavaScript syntax and conventions.

**Other Alternatives**

Other methods that could be tested for array iteration include:

* `forEach`: A more concise version of `array.forEach()` with a simpler syntax.
* `for...of` loop: A modern iteration method that's gaining popularity.
* Custom loops or hand-rolled iterators using `Array.prototype.forEach` or other native methods.

Keep in mind that the benchmark is specifically designed to compare `array.forEach()` and `array.reduce()`, so these alternatives might not be directly relevant.

Related benchmarks:

array.forEach() vs .reduce test2 (version: 0)

Comparing performance of: array.forEach() vs array.reduce()

Created: 5 years ago by: Guest

Jump to the latest result

array.forEach()

array.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):