Benchmark: Filter + ForEach vs ForEach with If

Script Preparation code:

var data = Array(10000).fill(0).map((_, i) => i);

Tests:

Filter + ForEach
data.filter(v => v % 2 === 0).forEach(value => { Math.random(); });
ForEach with If
data.forEach(value => { if (value % 2 === 0) { Math.random(); } });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Filter + ForEach
ForEach with If

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 26 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Windows

View result in a separate tab

Test name	Executions per second
Filter + ForEach	18486.4 Ops/sec
ForEach with If	27157.1 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared options, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark measures two different approaches to iterating over an array in JavaScript:

1. **Filter + ForEach**: This approach filters out every other element from the array using `Array.prototype.filter()` and then iterates over the remaining elements using `Array.prototype.forEach()`. Inside the callback function, it uses `Math.random()` to simulate some work being done.
2. **ForEach with If**: This approach directly iterates over the original array using `Array.prototype.forEach()`, checks if each element is even (using a conditional statement), and if so, performs some work using `Math.random()`.

**Options Compared**

The two options differ in how they handle iterating over the array:

* **Filter + ForEach**: Uses filtering to reduce the array size before iteration.
* **ForEach with If**: Iterates directly over the original array without filtering or reducing its size.

**Pros and Cons of Each Approach**

1. **Filter + ForEach**:
	* Pros:
		+ Can be faster for large arrays since it reduces the number of elements to process.
		+ Can take advantage of the filter method's optimized implementation.
	* Cons:
		+ Requires an additional filtering step, which can introduce overhead.
		+ May incur higher memory usage due to the temporary array created during filtering.
2. **ForEach with If**:
	* Pros:
		+ No additional filtering or creation of intermediate arrays is required.
		+ Can be more predictable and easier to understand for simple use cases.
	* Cons:
		+ Can be slower for large arrays since it iterates over the entire original array.

**Library Usage**

None of the benchmark tests explicitly uses any JavaScript libraries beyond the built-in `Array.prototype` methods. However, if a library like Lodash were used in the test code, its `filter()` or `map()` functions might be used to achieve similar results.

**Special JS Feature or Syntax**

The benchmark does not use any special JavaScript features or syntax, such as async/await, generators, or classes. It only uses standard JavaScript syntax for iteration and conditional statements.

**Alternative Approaches**

Other alternatives could include:

* **Using a `for` loop**: Instead of using `Array.prototype.forEach()`, a traditional `for` loop could be used to iterate over the array.
* **Using `map()` instead of `forEach`**: If the purpose of the iteration is to transform the data rather than perform some side effect, `Array.prototype.map()` might be a more suitable choice.
* **Using SIMD instructions**: If performance-critical code needs to handle large arrays and is running on a platform that supports SIMD (Single Instruction, Multiple Data) instructions (e.g., WebAssembly or CPU-specific extensions), using optimized SIMD instructions for element-wise operations could provide significant performance gains.

Keep in mind that these alternatives might not be directly comparable to the original benchmark options, as they may require different code structures and optimization techniques.

Related benchmarks:

Filter + ForEach vs ForEach with If (version: 0)

Comparing performance of: Filter + ForEach vs ForEach with If

Created: 2 years ago by: Guest

Jump to the latest result

Filter + ForEach

ForEach with If

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):