Benchmark: new Set([x]).has vs [x].includes

Tests:

includes
return [42].includes(42)
has
return new Set([42]).has(42)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
includes
has

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
includes	29736040.0 Ops/sec
has	1861505.9 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):

LLMs can make mistakes. Check important info.

This benchmark compares two ways to check if an element exists in a list-like structure:

**1. `includes` Method:** This method is built into JavaScript arrays. It takes a value as an argument and returns `true` if the value exists in the array, otherwise `false`.

* **Pros:** Concise and readable syntax. 
   * **Cons:**  May be slightly slower than using `has` for very large sets due to its inherent iteration through elements.

**2. `Set.has` Method:** This method is part of the JavaScript Set object, which only stores unique values. It takes a value as an argument and returns `true` if the value exists in the set, otherwise `false`. In this benchmark, a new Set is created with the given array's elements before checking for the existence of the target value.

* **Pros:** Potentially faster than `includes` for large sets because Sets are optimized for membership checks (using hash tables internally).
   * **Cons:** Requires creating a new Set object, which incurs some overhead compared to simply using a built-in array method.

**Alternatives**

While `includes` and `has` are the two methods being benchmarked, there are other ways to check for an element's existence:

* **Manual Iteration (Loop):** You could loop through the elements of an array and compare each element to the target value. This is less efficient than using built-in methods.
* **Finding Index:** The `indexOf` method returns the index of a value in an array, or -1 if it's not found.

The choice between these methods depends on factors like:

* **Array Size:**  For small arrays, the performance difference may be negligible. For large arrays, `has` using Sets might be significantly faster.
* **Uniqueness Requirement:** If you need to ensure uniqueness of elements, using a Set is beneficial regardless of size.

**In summary:** The benchmark tests whether using the built-in `includes` method or creating a Set and using its `has` method for membership checks provides better performance.

Related benchmarks:

new Set([x]).has vs [x].includes (version: 1)

Comparing performance of: includes vs has

Created: 5 years ago by: Registered User

Jump to the latest result

includes

has

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):