Benchmark: set.has vs. array.includes large

Script Preparation code:

var a = [];
for(let i = 0; i < 100000; i++){
  a.push(i);
}
var b = new Set(a)

Tests:

includes
return a.includes(50000)
lookup
return b.has(50000)

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:

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

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Let's break down what's being tested in this JavaScript microbenchmark.

**Overview**

The benchmark is designed to compare the performance of two approaches: `Set.has()` and `array.includes()`. Specifically, it tests whether searching for an element (in this case, 50,000) in a large set (`b`) or an array (`a`) is faster.

**Options Compared**

Two options are being compared:

1. **`Set.has()`**: This method checks if an element exists in a `Set` object.
2. **`array.includes()`**: This method searches for the presence of a value in an array.

**Pros and Cons**

**`Set.has()`**:

Pros:

* Generally faster than `array.includes()` because it uses a hash table data structure, which provides constant-time performance (O(1)).
* Can be more efficient when dealing with large sets, as it avoids the overhead of iterating through the entire array.

Cons:

* Limited use cases: `Set.has()` is designed for searching for exact matches within a set. If you need to perform range queries or other operations on the set, this method may not be suitable.
* Requires JavaScript objects (i.e., sets) to work efficiently.

**`array.includes()`**:

Pros:

* More flexible and widely supported: can be used with any type of array, including arrays with duplicate elements.
* Can be used for range queries or other operations on the array.

Cons:

* Slower than `Set.has()`: needs to iterate through the entire array to find the element, resulting in linear-time complexity (O(n)).
* Less efficient when dealing with large arrays: has higher overhead compared to using a hash table data structure.

**Other Considerations**

* The benchmark uses a large array (`a`) with 100,000 elements and a `Set` object (`b`) initialized from this array. This allows for a fair comparison of the two methods.
* The test case doesn't consider edge cases like empty sets or arrays, which could affect performance.

**Library Used**

In this benchmark, no specific library is required or utilized beyond the built-in JavaScript `Set` and `array.includes()` methods.

**Special JS Features/Syntax**

None are explicitly mentioned in the provided code snippets. However, it's worth noting that some older versions of JavaScript (e.g., ECMAScript 3) didn't support `Set` objects, while more modern browsers support them.

**Alternatives**

For searching for elements in a set or array, other approaches include:

* Using a library like Lodash's `contains()` function
* Implementing your own binary search algorithm
* Utilizing data structures like a balanced binary search tree

Keep in mind that the best approach depends on the specific use case and requirements.

Related benchmarks:

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

Comparing performance of: includes vs lookup

Created: 5 years ago by: Guest

Jump to the latest result

includes

lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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