Benchmark: Lodash _.union vs native Set() (accurate)

HTML Preparation code:

<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js"></script>

Script Preparation code:

var a = [1, 2, 3, 4, 5]
var b = [3, 4, 5, 6, 7]

Tests:

_.union
var c = _.union(a, b)
spread to Set()
var c = new Set([...a, ...b])
spread to Set() and spread again
var c = new Set([...a, ...b]) var d = [...c]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
_.union
spread to Set()
spread to Set() and spread again

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
_.union	3418568.0 Ops/sec
spread to Set()	4079332.5 Ops/sec
spread to Set() and spread again	3878396.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's happening in this benchmark.

**What is tested:**

The benchmark compares the performance of three approaches:

1. Using Lodash's `_.union()` method to create a union of two arrays (`a` and `b`).
2. Creating a new `Set` object from the spread operator (`...`) applied to both arrays (`a` and `b`).
3. Creating a new `Set` object from the spread operator (`...`) applied to both arrays (`a` and `b`), and then spreading that set again.

**Options compared:**

* Lodash's `_.union()` method vs.
* Native JavaScript `Set` objects created using the spread operator (`...`)
* Creating a new `Set` object, spreading it, and then spreading that result again

**Pros and cons of each approach:**

1. **Lodash's `_.union()` method:**
	* Pros:
		+ Can be more convenient for working with arrays in certain situations.
		+ May perform better than native JavaScript methods if optimized by Lodash.
	* Cons:
		+ Requires including an external library (Lodash) which may add overhead.
		+ May not be as efficient as native JavaScript methods due to the overhead of a library call.
2. **Native JavaScript `Set` objects:**
	* Pros:
		+ Built-in and optimized for performance by the JavaScript engine.
		+ No external library dependencies.
		+ Can take advantage of native caching mechanisms if used correctly.
	* Cons:
		+ Requires understanding of spread operator usage and set creation.
		+ May require additional code to convert between array and set representations.

**Library: Lodash**

Lodash is a popular JavaScript utility library that provides a collection of functions for common tasks, such as working with arrays, objects, and more. In this case, `_.union()` is used to create a union of two arrays, which is what the benchmark is comparing against native JavaScript `Set` objects.

**Special JS feature/syntax:**

The benchmark uses the spread operator (`...`) which is a relatively recent addition to the JavaScript language (introduced in ECMAScript 2015). The spread operator allows for creating new arrays or sets by copying elements from an existing array or set. This syntax can be convenient but requires understanding of its usage and potential performance implications.

**Other alternatives:**

If you're interested in exploring alternative approaches, here are a few options:

* Using `Array.prototype.reduce()` to create a union of two arrays.
* Utilizing the `Map` data structure instead of `Set`, as it provides similar functionality with additional methods for manipulating keys and values.
* Implementing custom logic using bitwise operations or other low-level techniques.

However, these alternatives may not be as well-optimized or straightforward as the native JavaScript `Set` objects and spread operator usage.

Related benchmarks:

Lodash _.union vs native Set() (accurate) (version: 0)

Comparing performance of: _.union vs spread to Set() vs spread to Set() and spread again

Created: 7 months ago by: Registered User

Jump to the latest result

_.union

spread to Set()

spread to Set() and spread again

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):