Benchmark: push vs length as filter (2)

Script Preparation code:

var length = 2000;

const array = Array(length);
for (let i = 0, { length } = array; i < length; i += 1) {
  array[i] = i;
}

function push() {
  var a = [];
  for (let i = 0; i < length; i += 1) {
    if (i % 2) {
     a.push(i);
    }
  }
  return a;
}

function append() {
  var a = Array(length);
  var offset = 0;
  for (let i = 0; i < length; i += 1) {
    if (i % 2) {
      a[offset++] = i;
    }
  }
  a.length = offset;
  return a;
}

function filter() {
	return array.filter((v) => v % 2);
}

Tests:

push
var a = push();
length
var a = append();
filter
var a = filter();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push
length
filter

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided JSON benchmark.

**Benchmark Overview**

The benchmark is designed to compare three different approaches for filtering an array: using `push()`, using `append()` with manual length adjustment, and using the built-in `filter()` method.

**Approaches Compared**

1. **Push():**
	* This approach creates a new array `a` and pushes elements from the original array `array` into it using the `push()` method.
	* The loop iterates over the entire array, but only pushes every other element (i.e., `i % 2 === true`).
	* This approach is likely to be slower due to the overhead of creating a new array and pushing elements into it.
2. **Append():**
	* This approach creates an array `a` with a fixed length equal to the original array's length.
	* The loop iterates over the entire array, but only assigns every other element (`i % 2 === true`) to the corresponding index in the new array.
	* After filling the array, the length of the array is adjusted to match the actual number of elements added (`a.length = offset;`).
	* This approach might be faster than `push()` since it doesn't involve creating a new array, but it requires manual memory management and adjustment of the array's length.
3. **Filter():**
	* This approach uses the built-in `filter()` method to create a new array containing only every other element from the original array (`array.filter((v) => v % 2)`).
	* The `filter()` method is likely to be faster since it's a native JavaScript function optimized for performance.

**Pros and Cons**

* **Push():**
	+ Pros: Easy to understand, minimal memory allocation.
	+ Cons: Creates a new array, pushes elements in individual operations, may lead to unnecessary allocations.
* **Append():**
	+ Pros: Only uses existing memory, potentially faster than `push()`.
	+ Cons: Requires manual length adjustment, can be slower due to allocation and deallocation overhead.
* **Filter():**
	+ Pros: Native JavaScript function, optimized for performance, minimal memory allocation.
	+ Cons: May require additional parsing and filtering operations.

**Library Usage**

The benchmark uses the `Array` object and its methods (`push()`, `append()`) without any external libraries. However, it's worth noting that some browsers may have additional features or optimizations enabled in their JavaScript engines.

**Special JS Features/Syntax**

There are no special JS features or syntax mentioned in this benchmark. All code is written using standard JavaScript syntax and doesn't utilize any experimental features like ES modules, async/await, or decorators.

**Alternative Approaches**

Other approaches to filtering an array might include:

* Using `map()` instead of `filter()`, which returns a new array with the filtered elements.
* Using a library like Lodash or Ramda for more complex filtering operations.
* Using native WebAssembly (WASM) functions to accelerate performance-critical code paths.

Keep in mind that these alternatives may not be relevant to this specific benchmark, and their performance impact would depend on the specific use case.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.6 Safari/605.1.15

Browser/OS: Safari 16 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
push	4726.3 Ops/sec
length	4550.5 Ops/sec
filter	17017.0 Ops/sec

Related benchmarks:

push vs length as filter (2) (version: 0)

Comparing performance of: push vs length vs filter

Created: one year ago by: Registered User

Jump to the latest result

push

length

filter

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):