Benchmark: set.has vs. array.includes (big)

Script Preparation code:

var max = 10000
var a = [...Array(max).keys()]
var b = new Set(a)
var c = Math.floor(Math.random() * max)

Tests:

Array.includes
return a.includes(c)
Set.has
return b.has(c)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.includes
Set.has

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark being tested on MeasureThat.net.

**What is being tested?**

The provided benchmark tests two approaches for checking if an element exists in a large array: `array.includes()` and `Set.has()`. Specifically, it checks how fast each approach can iterate over the elements of a set (created from an array) to find out if a randomly generated number (`c`) is present.

**Options compared**

Two options are being compared:

1. **Array.includes()**: This method checks if an element exists in the array by iterating over its indices and checking for a match.
2. **Set.has()**: This method uses a hash table to store elements of the set, allowing for fast lookup and existence checks.

**Pros and Cons**

- **Array.includes():**
	+ Pros: widely supported and well-maintained across browsers and platforms.
	+ Cons:
		- Can be slow for large arrays due to iteration over indices.
		- May have performance issues if the array is sparse or has many duplicate values.
- **Set.has():**
	+ Pros:
		- Fast lookup times due to hash table implementation.
		- Efficient even with a large number of elements in the set.
	+ Cons:
		- Not all browsers and platforms support Sets or have efficient implementations.
		- Requires creating a Set object, which may incur additional overhead.

**Library used**

The `Set` data structure is being used here. A Set is a collection of unique values, ordered or unordered, that cannot contain duplicate elements. In JavaScript, the `Set` constructor takes an iterable (such as an array) and creates a set from its elements.

**Special JS feature or syntax**

This benchmark doesn't rely on any special JavaScript features or syntax. However, note that the use of the spread operator (`...Array(max).keys()`) to create an array from an iterable is a modern JavaScript feature introduced in ECMAScript 2015 (ES6).

**Other alternatives**

If you needed to implement either `array.includes()` or `Set.has()` manually without using these methods, alternative approaches would be:

- For `array.includes()`:
	+ Manually iterating over the array's indices and checking for a match.
- For `Set.has()`:
	+ Using a custom data structure like an associative array (map) to store elements.

In contrast to `Set.has()`, manually implementing such a lookup system would likely be slower, especially for large sets due to the overhead of managing a custom data structure.

MeasureThat.net's benchmark is designed to compare these common JavaScript methods' performance in real-world scenarios, providing valuable insights into how different approaches can optimize your code's execution speed.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/114.0

Browser/OS: Firefox 114 on Windows

View result in a separate tab

Test name	Executions per second
Array.includes	251549.3 Ops/sec
Set.has	1476977024.0 Ops/sec

Related benchmarks:

set.has vs. array.includes (big) (version: 0)

Comparing performance of: Array.includes vs Set.has

Created: 3 years ago by: Guest

Jump to the latest result

Array.includes

Set.has

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):