Benchmark: Lodash _.union vs native Set() v4

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) const d = c.includes(a => a===3)
Set()
var c = new Set(a, b) const d = c.has(3)
Set() convert back to array
var c = new Set(a, b)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
_.union
Set()
Set() convert back to array

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/119.0

Browser/OS: Firefox 119 on Linux

View result in a separate tab

Test name	Executions per second
_.union	3222084.8 Ops/sec
Set()	2211495.2 Ops/sec
Set() convert back to array	2234821.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is tested?**

The provided JSON represents a benchmark test between three approaches:

1. **Lodash _.union**: A function from the popular Lodash library that performs union on two arrays.
2. **Native Set() v4**: The built-in `Set` data structure in modern JavaScript engines, which can be used to store unique values.

The benchmark tests the performance of these two approaches:

* Creating a set from two arrays using `new Set(a, b)` (Test Name: "Set()")
* Converting a set back to an array (Test Name: "Set() convert back to array")
* Performing union on two arrays using Lodash _.union (Test Name: "_.union")

**Options compared**

The three options are:

1. **Lodash _.union**: A function that performs union on two arrays.
2. **Native Set() v4**: The built-in `Set` data structure in modern JavaScript engines, which can be used to store unique values.
3. **Converting set back to array**: Converting the result of a set operation back to an array using the spread operator or other methods.

**Pros and Cons**

Here's a brief summary:

* **Lodash _.union**:
	+ Pros: Often faster than native Set() due to optimized implementation, easy to use.
	+ Cons: Requires additional library dependencies, may not be as efficient for very large datasets.
* **Native Set() v4**:
	+ Pros: Built-in data structure, no additional library dependencies, can be more efficient for large datasets.
	+ Cons: May have performance issues with small or sparse datasets, less intuitive API compared to _.union.
* **Converting set back to array**:
	+ Pros: Can be a good middle ground between Lodash _.union and native Set() v4, allows for easy conversion to other data structures.
	+ Cons: May incur additional overhead due to array creation, may not be as efficient as optimized implementation.

**Special JS feature or syntax**

None mentioned in the provided JSON. However, it's worth noting that modern JavaScript engines have many features and optimizations that can impact performance, such as:

* **Array.prototype.reduce()**: A popular method for performing aggregate operations on arrays.
* **Set.prototype.has()**: A simple method for checking if an element exists in a set.

**Other alternatives**

Some alternative approaches to consider when working with sets and unions:

* Using the `Map` data structure instead of `Set`, which can provide faster lookup times.
* Utilizing specialized libraries like [lodash-es](https://github.com/lodashjs/lodash-es) or [fast-set](https://github.com/sindresorhus/-fast-set) for optimized set operations.

Keep in mind that the best approach often depends on the specific use case and performance requirements.

Related benchmarks:

Lodash _.union vs native Set() v4 (version: 0)

Comparing performance of: _.union vs Set() vs Set() convert back to array

Created: one year ago by: Guest

Jump to the latest result

_.union

Set()

Set() convert back to array

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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