Benchmark: filter + forEach vs forEach

Script Preparation code:

arr = [];
for (let i = 0; i < 12345; i++) {
  arr[i] = ({ id: i });
}

function someFn(i) {
  return (i * 3 * 8 / 1200 * 0.002 / 40 * 0.2);
}

sumForEachFilter = 0
sumForEach = 0

Tests:

filter + forEach
arr.filter((i) => 'id' in i).forEach(({ id }) => { sumForEachFilter += someFn(id); })
forEach + if
arr.forEach((i) => { if('id' in i) { sumForEach += someFn(i.id); } })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
filter + forEach
forEach + if

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.

**Benchmark Explanation**

The provided benchmark measures the performance difference between two approaches: using `Array.prototype.filter()` followed by `Array.prototype.forEach()` versus using a simple `if` statement inside `Array.prototype.forEach()`.

In both test cases, an array of 12,345 objects is created, each with an `id` property. A function `someFn(i)` is defined to calculate a value based on the `id`. The goal is to sum up the results of this calculation for all elements in the array using one of these two approaches.

**Approach Comparison**

1. **Filter + forEach**:
	* Pros:
		+ More concise and easier to read.
		+ Takes advantage of the filtering process to eliminate unnecessary iterations.
	* Cons:
		+ May incur additional overhead due to filtering, which can be slower for large arrays.
2. **forEach + if**:
	* Pros:
		+ Can be faster for large arrays since it doesn't filter out elements prematurely.
	* Cons:
		+ More verbose and harder to read.

**Library Usage**

There is no explicit library usage in these test cases, but the `Array.prototype` methods used (e.g., `filter()`, `forEach()`) are built-in JavaScript methods. However, some browsers might have additional polyfills or implementations that can affect performance.

**Special JS Features/Syntax**

The benchmark uses the following feature:

* **Arrow functions**: Used in the `Array.prototype.filter()` and `someFn()` function definitions.
	+ Arrow functions are a concise way to define small functions. They are optimized for better performance compared to traditional function expressions.
	+ However, they may not be supported in older browsers or environments.

**Alternative Approaches**

Other possible approaches to measure this performance difference:

* Using `Array.prototype.map()` instead of `forEach()`: This would create a new array with the filtered results, which could affect performance.
* Adding more complex filtering conditions: Introducing additional filtering criteria can impact performance due to increased overhead.
* Using parallel processing or concurrent execution: Measuring the performance difference between sequential and parallel execution strategies can provide valuable insights.

For a more comprehensive benchmark, you might consider exploring these alternative approaches and comparing their performance with the existing ones.

Related benchmarks:

filter + forEach vs forEach (version: 0)

2

Comparing performance of: filter + forEach vs forEach + if

Created: 2 years ago by: Guest

Jump to the latest result

filter + forEach

forEach + if

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):