Benchmark: set.has vs. array.includes first element

Script Preparation code:

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

Tests:

includes
return a.includes(1)
lookup
return b.has(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:

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

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Let's break down the provided JSON and explain what's being tested.

**Benchmark Overview**

The benchmark is designed to compare two approaches for checking if an element exists in an array: using `array.includes()` or accessing the first element of the array using `array[0]` and then checking with `===`.

**Options Compared**

Two options are compared:

1. **Using `array.includes()`**: This method searches for the specified value in the array, returning a boolean indicating whether it was found.
2. **Accessing the first element of the array and comparing**: This approach checks if the first element of the array is equal to the target value using the triple equals operator (`===`).

**Pros and Cons**

* **Using `array.includes()`**:
	+ Pros: Efficient, as it only searches for the specified value in the array.
	+ Cons: May be slower than direct array access if the search is not optimized (e.g., using `Array.prototype.findIndex()`).
* **Accessing the first element of the array and comparing**:
	+ Pros: Directly accessing the first element eliminates the need for a search algorithm, which can be faster in some cases.
	+ Cons: Requires indexing into the array, which may incur additional overhead.

**Library Used**

None is explicitly mentioned in the provided JSON. However, it's worth noting that `Set` data structure (used in the "Script Preparation Code") provides an efficient way to check for membership using `has()` or `includes()`. The difference lies in how these methods are implemented:

* `Set.prototype.has()` checks if a value is present in the set by iterating over its internal array.
* `Set.prototype.includes()` returns `true` if the value is present, and `false` otherwise. It's essentially a wrapper around `has()`, but might be optimized for certain use cases.

**Special JS Feature/Syntax**

None are explicitly mentioned in this benchmark. However, it's worth noting that some modern JavaScript engines and browsers support advanced features like `Arrow functions`, which can affect the performance of the benchmark. But this is not relevant to the specific test case being compared here.

**Alternative Approaches**

Other alternatives for checking if an element exists in an array include:

* Using `Array.prototype.findIndex()` or a similar method, which returns the index of the first occurrence of the value (or -1 if not found).
* Using a library like Lodash's `findIndex()` function.
* Implementing your own custom search algorithm using bitwise operations or other optimization techniques.

It's essential to note that the choice of approach depends on the specific use case and performance requirements. The benchmark provided by MeasureThat.net is designed to compare the performance of these different approaches in a controlled environment.

Related benchmarks:

set.has vs. array.includes first element (version: 0)

Comparing performance of: includes vs lookup

Created: 3 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):