Benchmark: Set has vs object key reversed

Script Preparation code:

var obj = (new Array(1000)).fill(null).reduce((prev, newVal) => {prev[Math.random() + ''] = Math.random() + ''; return prev; }, { sausage: 'tst' });
var array = Object.keys(obj).reverse();
var set = new Set(array);

Tests:

Includes
array.includes('sausage')
Object[key]
obj['sausage']
Set.has
set.has('saudage')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Includes
Object[key]
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.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The provided JSON represents a benchmark definition, which defines three test cases:

1. `Set has vs object key reversed`: This test case compares the performance of three approaches to check if an array contains a value.
	* Approach 1: `array.includes('sausage')`
	* Approach 2: `obj['sausage']` (accessing an object property using a bracket notation)
	* Approach 3: `set.has('saudage')` (checking if a Set contains a value using the `has()` method)
2. `Includes`: This test case measures the performance of the `array.includes('sausage')` approach.
3. `Object[key]`: This test case measures the performance of the `obj['sausage']` approach.

**Options Compared**

The three approaches compared in the first test case are:

* **Approach 1: `array.includes()`**: This method checks if a specified value is present in the array. It uses binary search to find the value, which has an average time complexity of O(log n).
* **Approach 2: `obj['sausage']`**: This method accesses an object property using bracket notation. The JavaScript engine needs to look up the property in the object's prototype chain and then perform a lookup in the object itself. This approach has a variable time complexity, depending on the number of properties in the object.
* **Approach 3: `set.has()`**: This method checks if a specified value is present in the Set. It uses a hash table to store the elements and performs a constant-time lookup. The average time complexity of this approach is O(1).

**Pros and Cons**

Here's a summary of the pros and cons of each approach:

* **Approach 1: `array.includes()`**
	+ Pros: Fast and efficient, especially for large arrays.
	+ Cons: May not be suitable for very small arrays or arrays with a limited number of unique values.
* **Approach 2: `obj['sausage']`**
	+ Pros: Can be useful when working with objects that have a specific structure.
	+ Cons: Has a variable time complexity, which can lead to performance issues if the object is too large or has many properties.
* **Approach 3: `set.has()`**
	+ Pros: Fast and efficient, especially for sets with a large number of unique values.
	+ Cons: May not be suitable for situations where you need to iterate over all elements in the set.

**Library Usage**

The benchmark uses the `Set` object, which is a built-in JavaScript object that stores unique values. The `has()` method is used to check if a value is present in the Set.

**Special JS Features/Syntax**

None of the benchmarks use any special JavaScript features or syntax.

**Other Alternatives**

If you're interested in exploring alternative approaches for checking if an array contains a value, here are some other options:

* Using `indexOf()` method: This method returns the index of the specified value, or -1 if the value is not found. This approach has a time complexity of O(n), where n is the length of the array.
* Using a custom loop: You can write a simple loop to iterate over the array and check for the presence of the specified value. This approach also has a time complexity of O(n).

However, keep in mind that these alternative approaches may not be as efficient or scalable as the methods used in the benchmark.

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 121 on Android

View result in a separate tab

Test name	Executions per second
Includes	369331.2 Ops/sec
Object[key]	5299131.0 Ops/sec
Set.has	4516372.0 Ops/sec

Related benchmarks:

Set has vs object key reversed (version: 0)

performance comparison of ways to find if an array contains a value

Comparing performance of: Includes vs Object[key] vs Set.has

Created: 9 months ago by: Guest

Jump to the latest result

Includes

Object[key]

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):