Benchmark: Shorten array -- slice vs filter

Script Preparation code:

var test=Array.from({length: 110},()=>Math.random())

Tests:

Slice
test.slice(0,100)
Filter
test.filter((e,i)=> i + 10 > 100)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Slice
Filter

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36 Edg/145.0.0.0

Browser/OS: Chrome 145 on Windows

View result in a separate tab

Test name	Executions per second
Slice	9881657.0 Ops/sec
Filter	4375897.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of MeasureThat.net and explore the JavaScript microbenchmark you provided.

**Benchmark Overview**

The benchmark measures the performance difference between using `slice()` and `filter()` to shorten an array in JavaScript. The test case creates an array of 110 random numbers, then uses each method to reduce its length to 100 elements.

**Options Compared**

Two options are compared:

1. **`slice()`:** The `slice()` method returns a new array containing a subset of elements from the original array, starting at the specified index (`0`) and ending at the specified end index (`100`). This approach is simple and straightforward.
2. **`filter()`:** The `filter()` method creates a new array containing all elements that pass a test (in this case, the callback function `(e,i)=> i + 10 > 100`). This approach uses a filter to eliminate elements from the original array.

**Pros and Cons**

Here are some pros and cons of each approach:

* **`slice()`:**
	+ Pros:
		- Fast and efficient (O(1) time complexity)
		- Simple to implement
	+ Cons:
		- Can be less flexible than `filter()` if you need to perform more complex filtering operations
		- Creates a new array, which can lead to increased memory usage
* **`filter()`:**
	+ Pros:
		- More flexible and powerful than `slice()`, as it allows for custom filtering logic
		- Can be used with other methods (e.g., `map()` or `reduce()`) in combination
	+ Cons:
		- Generally slower than `slice()` due to the overhead of creating a new array and executing the callback function
		- Can lead to increased memory usage if not implemented carefully

**Library and Special JS Feature**

There are no external libraries used in this benchmark, but it does utilize a special JavaScript feature:

* **Arrow functions (`=>`)**: The `filter()` test case uses arrow functions to define the filtering callback function. Arrow functions provide a concise syntax for defining small, single-expression functions.

**Other Considerations**

When choosing between `slice()` and `filter()`, consider the following factors:

* **Performance**: If you need fast execution and can tolerate creating a new array, `slice()` might be a better choice.
* **Flexibility**: If you need to perform more complex filtering operations or want to combine this method with others, `filter()` is likely a better option.

**Alternatives**

If you're interested in exploring alternative methods for shortening an array, consider the following:

* **`map()` + `splice()`:** You can use `map()` to create a new array and then use `splice()` to remove elements from the original array.
* **`forEach()`**: While not as efficient as `slice()` or `filter()`, you can use `forEach()` to iterate over the array and push elements into a new array.

Keep in mind that these alternatives might have different performance characteristics and use more memory than the original methods.

Related benchmarks:

Shorten array -- slice vs filter (version: 0)

Comparing performance of: Slice vs Filter

Created: 2 years ago by: Guest

Jump to the latest result

Slice

Filter

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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