Benchmark: Find the index of an array which does not exist in another one.

Script Preparation code:

var a = [1, 2, 3, 4, 5, 6];
var b = [1, 2, 3, 4, 5];

Tests:

using set
const set = new Set(b); const lastNonCommonElement = a.find(element => !set.has(element)); const index = a.lastIndexOf(lastNonCommonElement);
using includes
const lastNonCommonElement = a.find(element => !b.includes(element)); const index = a.lastIndexOf(lastNonCommonElement);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
using set
using includes

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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**Benchmark Definition**

The benchmark is designed to measure the performance of finding the index of an array that does not exist in another one. In this specific case, we have two arrays: `a` and `b`. Array `a` contains all elements from 1 to 6, while array `b` is missing the element 6.

**Options Compared**

There are two approaches being compared:

1. **Using a Set**: The first test case uses a JavaScript `Set` data structure to store unique elements from array `b`. Then, it finds the last non-common element using the `find()` method and checks if it exists in the set using the `has()` method.
2. **Using includes()**: The second test case uses the `includes()` method to check if each element of array `a` is present in array `b`.

**Pros and Cons**

1. **Using a Set**:
	* Pros: Sets are optimized for fast lookups, making them ideal for this type of operation.
	* Cons: Creating a set from an array can be memory-intensive, especially for large arrays.
2. **Using includes()**:
	* Pros: `includes()` is a simple and intuitive method that doesn't require creating an additional data structure like a set.
	* Cons: The `includes()` method iterates over the elements of the array being searched, making it potentially slower than using a set.

**Library Usage**

In both test cases, we're using JavaScript's built-in `Set` object and `Array.prototype.includes()`. These are standard library functions that don't require any additional setup or imports.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax being used in this benchmark. Both approaches rely on the standard language features mentioned above.

**Alternative Approaches**

If we were to compare other approaches, some alternatives could be:

1. **Binary Search**: Implementing a binary search algorithm to find the last non-common element. This approach would require more complex logic and could be slower than using a set or `includes()`.
2. **Sorting and Indexing**: Sorting both arrays and then finding the index of the first difference. While this approach might be more straightforward, it would likely be slower due to the overhead of sorting.
3. **Using Math.random() and Array.prototype.indexOf()**: Using `Math.random()` to simulate an element being missing from array `b` and then using `Array.prototype.indexOf()` to find the index of the first difference. This approach could lead to poor performance due to the randomness introduced.

In summary, the benchmark compares two simple approaches: using a set or `includes()`. The "using includes()" method is currently faster according to the latest benchmark results, but both methods have their pros and cons regarding memory usage and iteration overhead.

Related benchmarks:

Find the index of an array which does not exist in another one. (version: 0)

Comparing performance of: using set vs using includes

Created: 2 years ago by: Guest

Jump to the latest result

using set

using includes

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):