Benchmark: set.has vs. array.includes counter

Script Preparation code:

var a = ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10'];
var b = new Set(a)
var c = 0

Tests:

includes
c += +a.includes(`${(Math.random() * 10) >> 0}`) > 5 ? 1 : -1
lookup
c += +b.has(`${(Math.random() * 10) >> 0}`) > 5 ? 1 : -1

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
includes
lookup

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser/OS: Firefox 133 on Linux

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Test name	Executions per second
includes	11994139.0 Ops/sec
lookup	29483812.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark in question compares the performance of two different methods to check for the presence of an element within a collection: using an array's `includes` method and a Set's `has` method. The benchmark examines how quickly each method can determine whether a randomly selected value (between 0 and 9) is present in the respective data structures.

### Options Compared
1. **Array's `includes` Method**
   - **Test Case**: `c += +a.includes(`${(Math.random() * 10) >> 0}`) > 5 ? 1 : -1`
   - **Description**: This test checks if a randomly generated number (in string form) is included in the array `a`. The `includes` method returns `true` if the value is present, otherwise `false`.

2. **Set's `has` Method**
   - **Test Case**: `c += +b.has(`${(Math.random() * 10) >> 0}`) > 5 ? 1 : -1`
   - **Description**: This test evaluates whether the same random number is present in the Set `b`. The `has` method returns `true` if the value exists in the Set.

### Pros and Cons

#### Array Includes
- **Pros**:
  - Familiarity: The `includes` method is a standard way to check for an element in an array which many developers are accustomed to.
  - Works well for small arrays when performance is less critical.
  
- **Cons**:
  - Performance: The `includes` method performs a linear search which means its time complexity is O(n). This can be relatively slow, especially for larger arrays.

#### Set Has
- **Pros**:
  - Performance: The `has` method in a Set uses a hash table for storage, allowing for average-case constant time complexity O(1) for lookups.
  - Ideal for checking existence without concern for order or duplicates.

- **Cons**:
  - Overhead: There is some overhead for creating a Set, especially when converting an existing array into a Set. For very small data sets or trivial applications, this overhead might not justify the performance improvement.

### Considerations
- **Data Structure Choice**: Choosing between arrays and Sets should depend on the use case. If you frequently need to check for the existence of elements, Sets are typically a better choice due to their faster lookup times. In contrast, if you need to maintain order or perform operations such as mapping or reducing, arrays may be more appropriate.
- **Randomness in Tests**: The use of `Math.random()` in the benchmarks attempts to simulate a variety of elements being searched for, which reflects a more realistic scenario of usage patterns.

### Alternative Methods
1. **Object-based Lookup**: An additional approach could involve using a plain object (as a hash map) for very fast lookups, similar to Sets. However, this would not naturally handle non-string types as keys without transformation, which can limit usability.
2. **Typed Arrays**: For numeric types, JavaScript has typed arrays that can be more memory-efficient, but they still do not address the issue of fast existence checks without additional logic.

### Conclusion
In general, comparing the two methods, using a Set would likely yield better performance for large datasets due to faster lookups. The benchmark results indicate this with a substantial difference in executions per second, highlighting the efficiency of the Set's `has` method over the array's `includes` in this usage context.

Related benchmarks:

set.has vs. array.includes counter (version: 1)

Comparing performance of: includes vs lookup

Created: one year ago by: Registered User

Jump to the latest result

includes

lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):