Benchmark: slice vs filter without spread

Script Preparation code:

var test=Array.from({length: 100},()=>Math.random())

Tests:

slice
const foo = test.slice(0,50); foo.push(test.slice(51))
filter
test.filter((e,i)=>i!=50)

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 the provided benchmark definition and test cases.

**What is being tested?**

The website, MeasureThat.net, allows users to create JavaScript microbenchmarks. The current benchmark compares two approaches: using `slice()` and `filter()` without spreading the array.

In this specific case, we're testing how many executions per second can be achieved by creating a new array with a subset of elements from the original array, and then pushing that subset into the original array.

**Options being compared**

There are two options being compared:

1. **`slice()`**: The `slice()` method returns a shallow copy of a portion of an array. It takes three arguments: the start index (inclusive), the end index (exclusive), and the length of the slice.
2. **`filter()` without spreading**: This approach uses the `filter()` method, which creates a new array containing all elements that pass a test implemented by a provided function.

**Pros and cons of each approach**

1. **`slice()`:**
	* Pros:
		+ Creates a shallow copy, which can be more efficient for large arrays.
		+ Directly returns the desired subset of elements.
	* Cons:
		+ Can create a new array object, even if it's not needed (if you're only assigning it to a variable).
2. **`filter()` without spreading:**
	* Pros:
		+ Only creates a new array if the filtering function is not null or undefined.
	* Cons:
		+ Can be slower than `slice()`, as it needs to iterate over all elements in the original array.

**Library and its purpose**

There isn't a specific library being used in this benchmark. However, the use of `Array.from()` suggests that the test case is using modern JavaScript features, specifically the `Array.prototype.from()` method, which was introduced in ECMAScript 2015 (ES6).

**Special JS feature or syntax**

The `slice` and `filter` methods are built-in methods of the Array prototype in JavaScript. They don't require any special library or syntax.

**Other alternatives**

If you wanted to implement this benchmark using alternative approaches, here are a few options:

1. **Using a custom function**: You could create a custom function that manually iterates over the array elements and constructs a new array with the desired subset of elements.
2. **Using `map()` instead of `filter`**: While not exactly equivalent, you could use the `map()` method to achieve similar results. However, keep in mind that `map()` creates a new array, whereas `filter()` does not.
3. **Using native WebAssembly or other optimization techniques**: Depending on your specific use case and performance requirements, you might consider using native WebAssembly (WASM) or other optimization techniques, such as caching or memoization.

Keep in mind that the best approach will depend on your specific performance requirements and the characteristics of your data. MeasureThat.net's benchmark is just one tool to help you compare different approaches; you may need to experiment with various methods to find the most efficient solution for your use case.

Related benchmarks:

slice vs filter without spread (version: 0)

Comparing performance of: slice vs filter

Created: 4 years ago by: Guest

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):