Benchmark: .filter().forEach() vs for with cached length

Script Preparation code:

var array = [{
            conn: Math.random() > 0.9
    },{
            conn: Math.random() > 0.9
    },{
            conn: Math.random() > 0.9
    },{
            conn: Math.random() > 0.9
    },{
            conn: Math.random() > 0.9
    },{
            conn: Math.random() > 0.9
    }
];

Tests:

fori
for (let i = 0, m = array.length; i < m; i++) { if (!array[i].conn) { array[i]; } }
.filter().foreach()
array.filter((a) => a.conn).forEach((a) => { a });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
fori
.filter().foreach()

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.

I'll break down the benchmark definition and test cases to explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark is comparing two approaches: `for` loop with cached length and `.filter().forEach()` method.

1. **Cached Length**: The `for` loop uses a cached value of the array length (`m`) instead of recalculating it on each iteration. This approach optimizes the loop by reducing the number of times the length is accessed.
2. **.filter().forEach()**: This approach uses the `.filter()` method to create a new array with only elements that satisfy the condition (in this case, `array[i].conn` being truthy), and then iterates over the filtered array using the `.forEach()` method.

**Pros and Cons**

1. **Cached Length**:
	* Pros:
		+ Reduces the number of times the length is accessed, which can improve performance.
		+ Can be more efficient when the loop doesn't need to access the entire array.
	* Cons:
		+ Requires an initial calculation of the length, which might be slower than accessing it directly.
2. **.filter().forEach()**:
	* Pros:
		+ Simplifies the code and makes it easier to read.
		+ Can be more efficient when working with large arrays or complex filtering conditions.
	* Cons:
		+ Creates a new array, which can lead to increased memory usage.
		+ Iterates over the filtered array, which might be slower than using a `for` loop.

**Library**

The benchmark doesn't use any external libraries. However, it does utilize JavaScript's built-in methods like `.filter()` and `.forEach()`, as well as basic arithmetic operations (`Math.random()`) and string concatenation.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. It only uses standard JavaScript constructs.

**Other Alternatives**

For similar benchmarks, you might consider testing other approaches, such as:

1. Using a `while` loop instead of a `for` loop.
2. Implementing the filtering and iteration logic manually using loops.
3. Comparing performance with different data structures (e.g., arrays vs. linked lists).
4. Testing the impact of caching on performance in other scenarios.

Keep in mind that the choice of approach often depends on the specific use case, requirements, and constraints.

Related benchmarks:

.filter().forEach() vs for with cached length (version: 0)

Comparing performance of: fori vs .filter().foreach()

Created: 4 years ago by: Registered User

Jump to the latest result

fori

.filter().foreach()

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):