Benchmark: slice vs filter perf

Script Preparation code:

var test=Array.from({length: 1000},()=>Math.random())

Tests:

slice
var numberOfValuesToKeep = 200; var start = test.length < numberOfValuesToKeep ? 0 : test.length - numberOfValuesToKeep; var end = test.length; test.slice(start, end);
filter
var numberOfValuesToKeep = 200; var start = test.length < numberOfValuesToKeep ? 0 : test.length - numberOfValuesToKeep; var end = test.length; test.filter((e,i)=>i>=start && i<= end);

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:

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this JavaScript microbenchmark.

**Benchmark Purpose:**
The benchmark is designed to compare the performance of two common array manipulation methods in JavaScript: `slice()` and `filter()`. The purpose is to determine which method is faster for a specific use case, where you need to retain a subset of elements from an array.

**Options Compared:**

1. **Slice()**: This method creates a shallow copy of the specified range of elements within the original array.
2. **Filter()**: This method creates a new array with all elements that pass the test implemented by the provided function.

**Pros and Cons of Each Approach:**

* **Slice():**
	+ Pros:
		- Creates a shallow copy, which can be beneficial for certain use cases (e.g., when you need to modify the original array).
		- Can be faster than `filter()` because it avoids the overhead of creating a new array.
	+ Cons:
		- Returns a new array object, which can lead to increased memory usage.
		- May not be suitable for use cases where you want to modify the original array or don't need a shallow copy.
* **Filter():**
	+ Pros:
		- Creates a new array with filtered elements, which can be beneficial when you don't need to modify the original array.
		- Can be faster than `slice()` because it avoids creating an intermediate copy of the array.
	+ Cons:
		- Returns a new array object, which can lead to increased memory usage.
		- May not be suitable for use cases where you need to preserve the original array's order or modify its elements.

**Library and Syntax Considerations:**
In this benchmark, neither `slice()` nor `filter()` rely on any external libraries. However, if you're using a library like Lodash (which includes these functions) in your production code, you may want to consider performance implications when choosing between `slice()` and `filter()`.

**Special JS Feature or Syntax:**
There are no special JavaScript features or syntaxes being tested in this benchmark. The code is written in plain JavaScript and uses standard array methods.

**Other Alternatives:**
If you're looking for alternative ways to subset an array, consider using:

1. **Array.prototype.slice()**: This is the most common way to subset an array.
2. **Array.prototype.slice.call()**: This method creates a new array from a specified range of elements in an existing array.
3. **Array.prototype.filter()**: As mentioned earlier, this method creates a new array with filtered elements.

Keep in mind that while these alternatives may offer different trade-offs, they can also impact performance and memory usage depending on the specific use case.

Related benchmarks:

slice vs filter perf (version: 0)

Comparing performance of: slice vs filter

Created: 4 years ago by: Registered User

Jump to the latest result

slice

filter

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):