Benchmark: Test Array filter speed

Tests:

Splice
const testArray = Array(1e5).fill(true) const newTestArray = testArray.splice(0, 8e4);
Concat
const testArray = Array(1e5).fill(true) const newTestArray = testArray.splice(0, 8e4).filter(e=>e);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Splice
Concat

Fastest: N/A

Slowest: N/A

Latest run results:

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

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I'll break down the benchmark and explain what's being tested, compared options, pros and cons, library usage, special JS features, and other considerations.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided JSON represents two individual test cases:

1. `Test Array filter speed` (with splicing)
2. `Test Array filter speed` (with concatenation)

These tests aim to measure the performance difference between using `splice()` and `concat()` when filtering a large array of true values.

**Options Compared**

The two options being compared are:

* **Splice**: Removes elements from an array by their position.
* **Concat**: Concatenates arrays using the spread operator (`...`).

**Pros and Cons**

1. **Splice**
	* Pros:
		+ Efficient for removing a portion of an array, as it only needs to shift elements after the removal point.
		+ Can be faster for large arrays due to its mutable nature.
	* Cons:
		+ Can be slower for small arrays due to overhead from modifying the original array.
2. **Concat**
	* Pros:
		+ Suitable for small arrays, as it creates a new array and doesn't modify the original.
		+ Faster for small arrays due to reduced overhead.
	* Cons:
		+ Inefficient for large arrays, as it creates multiple intermediate arrays.

**Library Usage**

None of the provided test cases use any external libraries. However, if you were to add a library, `splice()` is typically implemented using a combination of bitwise operations and array indexing, while `concat()` might use an algorithm that involves creating new arrays or shifting elements.

**Special JS Features**

The tests don't use any special JavaScript features other than the `const` keyword for declaring variables. However, if you were to modify the tests, you could introduce features like:

* Generators: Using a generator function to create large arrays
* Iterables: Using an iterable object, like a Map or Set, as the source array
* Arrow functions: Using arrow functions for concise code

**Other Considerations**

When running these benchmarks, consider the following factors that might affect results:

* **Array size**: Larger arrays will likely favor `splice()` due to its mutable nature.
* **Array contents**: If the array contains duplicate values or objects with complex properties, this might impact performance differences between `splice()` and `concat()`.
* **Browser performance**: Different browsers may optimize their implementations of `splice()` and `concat()` differently.

**Alternatives**

If you're looking for alternative approaches to benchmarking JavaScript performance:

1. **V8 Profiler**: A built-in profiling tool in Chrome that allows you to analyze JavaScript execution time.
2. **Benchmark.js**: An open-source library specifically designed for creating and running microbenchmarks.
3. **jsperf**: A simple, old-school benchmarking tool that uses a similar approach to MeasureThat.net.

Remember to always consider the specific requirements of your use case when choosing a benchmarking approach or library.

Related benchmarks:

Test Array filter speed (version: 0)

Comparing performance of: Splice vs Concat

Created: 3 years ago by: Guest

Jump to the latest result

Splice

Concat

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):