Benchmark: Javascript unique string array

Tests:

Using an object
const nonUnique = ['one', 'two', 'three', 'three', 'four', 'four', 'five', 'six', 'seven', 'eight', 'nine']; const unique = Object.keys(nonUnique.reduce((acc, item) => { if (!acc[item]) { acc[item] = true }; return acc; }, {}));
Using a Set
const nonUnique = ['one', 'two', 'three', 'three', 'four', 'four', 'five', 'six', 'seven', 'eight', 'nine']; const unique = Array.from(new Set(nonUnique));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using an object
Using a Set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 26 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using an object	4096806.5 Ops/sec
Using a Set	3258714.8 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 and explore what's being tested in this benchmark.

**Benchmark Overview**

This benchmark compares two approaches to remove duplicate strings from an array: using an object and using a Set. The goal is to create a unique array of strings from a possible non-unique array.

**Options Compared**

Two options are compared:

1. **Using an object**: This approach uses the `Object.keys()` method to get an array of unique keys from an object, where each key is a string. The `reduce()` method is used to iterate over the original array and add each item to the object only if it's not already present.
2. **Using a Set**: This approach uses the `Set` data structure to automatically eliminate duplicates. It converts the array to a Set using `Array.from(new Set(nonUnique))`, which returns an array of unique strings.

**Pros and Cons**

**Using an Object:**

Pros:

* Can handle non-unique arrays with arbitrary key values.
* Does not require any additional libraries or imports.

Cons:

* Can be slower than the Set approach, especially for large datasets, since it involves creating an object and iterating over its keys.
* May have performance issues if the array is very large, as it requires more memory to store the object.

**Using a Set:**

Pros:

* Fast and efficient, as Sets are optimized for lookup and uniqueness.
* Does not require any additional libraries or imports.

Cons:

* Requires the `Set` data structure, which may not be available in older browsers or environments.
* May not work correctly if the array contains non-string values or objects with non-unique properties.

**Other Considerations**

When choosing between these two approaches, consider the specific requirements of your use case. If you need to handle non-unique arrays with arbitrary key values, using an object might be a better choice. However, if performance is critical and you're working with large datasets, using a Set could be a better option.

**Library/Dependencies**

Neither of these approaches requires any additional libraries or dependencies beyond what's built into JavaScript. However, the `Set` data structure is optimized for specific browsers and environments, so it may not work correctly in older or less-capable browsers.

**Special JS Feature/Syntax**

The `reduce()` method and the `Object.keys()` method are part of the standard JavaScript syntax. However, some features like array destructuring (`Array.from(new Set(nonUnique))`) might be more recent additions to the language, introduced in ECMAScript 2015 (ES6).

Related benchmarks:

Javascript unique string array (version: 0)

Create a unique array of strings from a possible non-unique array.

Comparing performance of: Using an object vs Using a Set

Created: one year ago by: Registered User

Jump to the latest result

Using an object

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):