Benchmark: Methods to remove duplicates from array (fork)

Script Preparation code:

var array = [];
for (let i = 0; i < 100000; i++) {
   array.push(Math.floor((Math.random() * 10) + 1));
}

Tests:

Using indexOf
array.filter((item, index) => array.indexOf(item) != index);
Using lastIndexOf
array.reduce((unique, item) => unique.includes(item) ? unique : [...unique, item], []);
Using a Set
[...new Set(array)]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using indexOf
Using lastIndexOf
Using a Set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.75 Safari/537.36

Browser/OS: Chrome 100 on Windows

View result in a separate tab

Test name	Executions per second
Using indexOf	82.9 Ops/sec
Using lastIndexOf	346.4 Ops/sec
Using a Set	768.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is tested?**

The provided benchmark tests three different approaches to remove duplicates from an array:

1. Using `indexOf` (index-based method)
2. Using `lastIndexOf` (index-based method, but with a twist)
3. Using a Set data structure

Each approach is implemented in a separate test case.

**Options compared**

We have three options being compared:

* **Index-based methods**: These methods use the `indexOf` or `lastIndexOf` functions to find the index of each item in the array. The main difference between these two methods is that `lastIndexOf` returns the last index of the item, whereas `indexOf` returns the first index.
* **Set data structure**: This approach uses a Set data structure to store unique items from the array.

**Pros and Cons**

Here are some pros and cons for each approach:

* **Index-based methods (Using indexOf and Using lastIndexOf)**:
	+ Pros: Simple to implement, widely supported by browsers.
	+ Cons: May be slower than other approaches due to the need to iterate over the entire array. Also, `lastIndexOf` may not work as expected if the item is not found in the beginning of the array.
* **Set data structure (Using a Set)**:
	+ Pros: Fast and efficient, as it uses a hash table to store unique items.
	+ Cons: Requires additional memory to store the Set data structure, which may be a concern for very large arrays.

**Library and purpose**

In this benchmark, we can see that two libraries/libraries-like-technologies are used:

* None of these are explicitly mentioned in the json. However, since one of the tests is using a "Set", a similar concept exists: `Set` (ECMAScript 2015) - which allows to create and store unique values.

**Special JS feature or syntax**

There is no explicit mention of any special JavaScript features or syntax being used in this benchmark. The implementation focuses on simple, standard JavaScript methods.

**Other alternatives**

In general, other approaches to remove duplicates from an array include:

* Using a `Map` data structure (similar to a Set, but with additional capabilities)
* Using a custom sorting algorithm that removes duplicates
* Using a library like Lodash or Underscore.js, which provide various functions for removing duplicates.

However, these alternatives are not being tested in this specific benchmark.

In summary, the MeasureThat.net benchmark tests three approaches to remove duplicates from an array: index-based methods using `indexOf` and `lastIndexOf`, and a Set data structure. Each approach has its pros and cons, and we can see that the Set data structure is the fastest and most efficient option in this particular test case.

Related benchmarks:

Methods to remove duplicates from array (fork) (version: 0)

Comparing performance of: Using indexOf vs Using lastIndexOf vs Using a Set

Created: 2 years ago by: Guest

Jump to the latest result

Using indexOf

Using lastIndexOf

Using a Set

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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