Benchmark: Set vs Array Privilege Check

Script Preparation code:

var i = Math.floor(Math.random() * 500) + 1;
var a = [...Array(500).keys()];
var b = new Set(a);

Tests:

Includes Performance
return a.includes(i);
Has Performance
return b.has(i);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Includes Performance
Has Performance

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Includes Performance	93628608.0 Ops/sec
Has Performance	110882352.0 Ops/sec

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 and explain what's being tested.

**Benchmark Overview**

The benchmark measures the performance of two different approaches to check if an element exists in a Set or Array:

1. `a.includes(i)`
2. `b.has(i)`

Here, `a` is an Array created with 500 elements from `Array(500).keys()`, and `b` is a Set created from the same array.

**Options Compared**

The benchmark compares two options:

A) Using the `includes()` method on an Array (`a.includes(i)`)

B) Using the `has()` method on a Set (`b.has(i)`)

**Pros and Cons of Each Approach**

**A) Using includes() on an Array:**

Pros:

* Widely supported in most browsers
* Easy to implement

Cons:

* Has a linear search algorithm, which can be slow for large arrays
* May not be optimized by the browser's engine

**B) Using has() on a Set:**

Pros:

* Has a constant-time lookup (O(1)) on average, making it faster than Array.includes()
* Optimized by most browsers' engines

Cons:

* Not supported in older browsers or those with limited Set support
* Requires creating a Set object

**Library Usage**

In this benchmark, the `Set` library is used to create a set from the array elements. Sets are data structures that store unique values and provide fast membership testing.

The purpose of using a Set here is to demonstrate the performance difference between checking existence in an Array versus a Set.

**Special JS Feature or Syntax**

There isn't any special JavaScript feature or syntax mentioned in this benchmark. The focus is on comparing two basic operations: `includes()` on an Array and `has()` on a Set.

**Other Alternatives**

If you want to compare other approaches, here are some alternatives:

* Using `indexOf()` on an Array (`a.indexOf(i)`)
* Using `filter()` on an Array (not applicable in this case, since we're looking for existence)
* Using regular expressions with the `test()` method

Keep in mind that each alternative may have its own pros and cons, and some might not be supported or optimized by all browsers.

Related benchmarks:

Set vs Array Privilege Check (version: 0)

Comparing performance of: Includes Performance vs Has Performance

Created: one year ago by: Guest

Jump to the latest result

Includes Performance

Has Performance

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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