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

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)
Set()
var c = new Set(a, b)
Set() convert back to array
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
Set()
Set() convert back to array

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Slowest: N/A

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

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**Overview of the Benchmark**

The provided benchmark compares the performance of three approaches for performing set operations in JavaScript:

1. Using Lodash's `_.union` function
2. Creating a new Set object and using its `add()` method to add elements from two arrays
3. Creating a new Set object, adding elements from two arrays, and then converting it back to an array using the spread operator (`[...]`)

**Library: Lodash**

Lodash is a popular JavaScript utility library that provides a set of reusable functions for common tasks, including array manipulation. In this benchmark, Lodash's `_.union` function is used to compare its performance with native Set operations.

The `_.union` function takes two arrays as input and returns a new array containing all unique elements from both arrays.

**Native Set Operations**

Creating a new Set object allows you to efficiently store and look up elements. The `add()` method is used to add elements to the set, which has an average time complexity of O(1).

Converting a Set back to an array using the spread operator (`[...]`) has a time complexity of O(n), where n is the number of elements in the set.

**Performance Comparison**

The benchmark results show that:

* Creating a new Set object and adding elements from two arrays (option 2) is the fastest approach, with an average execution speed of approximately 316,7891.0 executions per second.
* Converting a Set back to an array using the spread operator (`[...]`) (option 3) is slower than option 2 but still relatively fast, with an average execution speed of approximately 16,378,910.0 executions per second.
* Using Lodash's `_.union` function (option 1) is the slowest approach, with an average execution speed of approximately 3,167,911.0 executions per second.

**Pros and Cons**

Here are some pros and cons for each approach:

* **Option 2: Creating a new Set object**
	+ Pros:
		- Fastest approach
		- Most efficient use of memory
	- Cons:
		- Requires manual addition of elements using `add()` method
* **Option 3: Converting a Set to an array using the spread operator**
	+ Pros:
		- Easy to implement and understand
		- No need to manually manage element addition
	- Cons:
		- Slower than option 2
		- Requires extra memory for creating a new array
* **Option 1: Using Lodash's `_.union` function**
	+ Pros:
		- Easy to implement and understand
	+ Cons:
		- Slowest approach
		- Requires an additional library dependency

**Other Alternatives**

If you're looking for alternative approaches, consider the following:

* **Using Array.prototype.reduce()`**: This method allows you to perform set operations using a more functional programming style. However, it may be slower than option 2 or option 3.
* **Using Array.prototype.concat()` and `Set`**: This approach combines the benefits of options 2 and 3 by creating a new Set object and then concatenating an array of values using `concat()`. However, it may still be slower than option 2.

In conclusion, when performing set operations in JavaScript, consider using native Set objects (option 2) for optimal performance. If you prefer a more functional programming style or need to handle large datasets efficiently, explore alternative approaches like Array.prototype.reduce() or using an array with a Set object.

Related benchmarks:

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

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

Created: 4 years ago by: Guest

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_.union

Set()

Set() convert back to array

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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