Benchmark: Array filter vs. for loop (fixed really really)

Script Preparation code:

var arr = [1,2,3,4,5,6,7,8,9,0], farr;

Tests:

Filter
farr = arr.filter(function(item) { return (item>4); });
For
for (var i=0,len=arr.length;i<len;i++) { if (arr[i]<5) continue; farr.push(arr[i]); }
For 2
for (var i=0,len=arr.length;i<len;i++) { if (arr[i]>4) farr.push(arr[i]); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Filter
For
For 2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 months ago)

User agent: Mozilla/5.0 (Android 15; Mobile; rv:148.0) Gecko/148.0 Firefox/148.0

Browser/OS: Firefox Mobile 148 on Android

View result in a separate tab

Filter

12.8M/s

For

3.7M/s

For 2

2.9M/s

View exact numbers

Test name	Executions per second
✓ Filter	12,783,667 Ops/sec
For	3,734,460 Ops/sec
For 2	2,874,524 Ops/sec

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, along with the pros and cons of each approach.

**Benchmark Overview**

The test measures the performance difference between two approaches to filter an array: using the `Array.prototype.filter()` method versus traditional `for` loops. The test case is designed to ensure consistency across different browsers and platforms.

**Options Compared**

1. **Array.prototype.filter()**: This method creates a new array with all elements that pass the test implemented by the provided function.
2. **Traditional for loops**: Two variations are tested:
	* `For 1`: Iterates over the array using a traditional `for` loop, pushing elements to a new array (`farr`) if they meet the condition.
	* `For 2`: Similar to `For 1`, but pushes elements directly into the original array (`farr`), instead of creating a new one.

**Pros and Cons**

**Array.prototype.filter()**

Pros:

* More concise and readable code
* Creates a new array, which can be beneficial for performance in some cases (e.g., when working with large datasets)

Cons:

* Requires an additional memory allocation for the new array, potentially leading to higher memory usage
* May not be as efficient as traditional loops if the filter condition is complex or expensive to evaluate

**Traditional for loops**

Pros:

* No additional memory allocation required
* Can be more efficient for simple filter conditions, as it avoids creating a new array

Cons:

* Code can become more verbose and harder to read
* May lead to issues with variable scope and loop counter management if not implemented carefully

**Library Usage**

In the benchmark definition script, the `filter()` method is used. This is a standard JavaScript method provided by the Array prototype, which filters elements in an array based on a provided function.

**Special JS Feature or Syntax**

None are mentioned in this specific test case.

**Considerations**

When choosing between these approaches, consider the following:

* If performance is critical and memory allocation is not a concern, traditional for loops might be preferred.
* If code readability and conciseness are more important, `Array.prototype.filter()` might be a better choice.
* In most cases, the difference in performance between these two approaches will be negligible. However, if you're working with large datasets or need to optimize specific filter conditions, experimentation with different approaches may reveal subtle differences.

**Alternatives**

Other alternatives for filtering arrays include:

1. `Array.prototype.map()` and `Array.prototype.reduce()`: While not directly applicable to simple filtering, these methods can be used in combination with other functions to achieve similar results.
2. Libraries like Lodash or Ramda, which provide more functional programming-style filtering options.

Note that the choice of approach ultimately depends on the specific use case, personal preference, and performance requirements.

Array filter vs. for loop (fixed really really) (version: 0)

Comparing performance of: `Filter vs For vs For 2`

Created: 9 years ago by: Registered User

Go to the latest result

Filter

For

For 2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Array filter vs. for loop (fixed really really) (version: 0)

Comparing performance of: Filter vs For vs For 2

Created: 9 years ago by: Registered User

Go to the latest result

Filter

For

For 2

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `Filter vs For vs For 2`