Benchmark: Remove from array

Script Preparation code:

var letters = ["A", "B", "C", "D", "E", "F"];

Tests:

Default
var copy = letters.slice(); var length = copy.length; for (var i = 0; i < length; i++) { if (copy[i] === "B" || copy[i] === "C") { letters.splice(letters.indexOf(copy[i]), 1); } }
Reverse
var copy = letters.slice(); var length = copy.length; for (var i = length - 1; i >= 0; i--) { if (copy[i] === "B" || copy[i] === "C") { letters.splice(i, 1); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Default
Reverse

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 world of JavaScript microbenchmarks!

**What is tested?**

The provided JSON represents a benchmark test case that measures the performance of removing elements from an array in JavaScript. The test involves creating a copy of the original array, iterating over the copy to find and remove specific elements (in this case, "B" or "C"), and then modifying the original array by removing those same elements.

**Options compared**

There are two different approaches being tested:

1. **Default**: This approach uses a traditional for loop with `i < length` condition to iterate over the copy of the array. The loop starts from the beginning of the array and removes elements as it finds them.
2. **Reverse**: This approach uses a for loop with `i >= 0` condition to iterate over the copy of the array in reverse order. The loop starts from the end of the array and removes elements as it finds them.

**Pros and cons**

* **Default**:
	+ Pros: More traditional and straightforward approach, easier to understand.
	+ Cons: May be slower due to iterating over the entire array multiple times (e.g., `indexOf` and then removing).
* **Reverse**:
	+ Pros: Can be faster since it only iterates over the array once in reverse order.
	+ Cons: Requires careful consideration of edge cases, especially when dealing with large arrays or arrays that are frequently modified.

In general, the Reverse approach can be beneficial for performance-critical code paths where every cycle counts. However, it's essential to weigh this against the potential complexity and overhead of managing a reversed iteration.

**Library usage**

There is no explicit library used in this benchmark test case. The `slice()` method is a built-in JavaScript array method that creates a shallow copy of an array.

**Special JS features or syntax**

There are two special aspects to note:

* **Array indexing**: The `indexOf` method returns the index at which the first occurrence of the specified element can be found in the array. This allows us to remove elements from the original array while still iterating over its indices.
* **For loop iteration**: The for loop iterates over the copy of the array using a variable (`i`) that is updated automatically by the compiler. This approach avoids manual indexing and reduces code complexity.

**Other alternatives**

Some alternative approaches might include:

* Using `filter()` to create a new array with filtered elements, rather than modifying the original array.
* Employing a more efficient data structure, such as a Set or Map, to store unique elements being removed from the array.
* Utilizing optimized JavaScript engines' built-in optimizations for array removals.

Keep in mind that these alternatives would likely introduce additional complexity and might not provide significant performance benefits in this specific benchmark scenario.

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36

Browser/OS: Chrome 54 on Windows 7

View result in a separate tab

Test name	Executions per second
Default	2366346.2 Ops/sec
Reverse	2494599.8 Ops/sec

Related benchmarks:

Remove from array (version: 0)

Remove from array

Comparing performance of: Default vs Reverse

Created: 7 years ago by: Guest

Jump to the latest result

Default

Reverse

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):