Benchmark: Array immutable union: lodash union vs flatten and creating a new set

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var list = [[ 'a', 'b', 'c' ], [ 'b', 'd', 'a', 'e', 'f' ]];

Tests:

lodash union
var c = _.union(...list);
Set from flatten
var c = new Set(_.flatten(list))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash union
Set from flatten

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Linux

View result in a separate tab

Test name	Executions per second
lodash union	3416284.0 Ops/sec
Set from flatten	3536885.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its options.

**Benchmark Overview**

The benchmark is designed to compare two approaches for performing an immutable union operation on an array of arrays in JavaScript. The test uses Lodash, a popular utility library for JavaScript.

**Options Compared**

Two options are compared:

1. `lodash union` (via `_union()` method): This approach uses the `_.union()` function from Lodash to perform the union operation.
2. `Set from flatten` (via `new Set() and _.flatten()`): This approach first flattens the array of arrays using `_.flatten()` and then creates a new Set object from the flattened result.

**Pros and Cons**

1. `lodash union`:
	* Pros: More concise and readable code, as it leverages Lodash's optimized implementation.
	* Cons: May not be as efficient as the alternative approach, depending on the JavaScript engine and optimizations used by Lodash.
2. `Set from flatten`:
	* Pros: Can be more efficient than the Lodash approach, especially for large datasets, as it avoids the overhead of a function call and uses native JavaScript data structures (Sets).
	* Cons: Requires additional code to create and manage the Set object, which may make the code slightly less readable.

**Lodash Library**

Lodash is a utility library that provides a wide range of functions for working with JavaScript arrays, objects, and other data structures. The `_.union()` function is part of this library, providing an efficient implementation of the union operation.

**Special JavaScript Feature/Syntax**

The benchmark uses the `...` spread operator to pass multiple arrays as separate arguments to the `_union()` function, which is a feature introduced in ECMAScript 2015 (ES6). This allows for concise and expressive code when working with array operations.

**Other Alternatives**

If you're looking for alternative approaches or alternatives to Lodash, consider the following:

1. `Array.prototype.reduce()`: You can use `reduce()` to perform an accumulator-based union operation on arrays.
2. Manual iteration: You can iterate over the arrays and add elements to a new array or Set object manually, without relying on any library functions.

Here's a simple example of using `reduce()` for the `lodash union` equivalent:
```javascript
var list = [[ 'a', 'b', 'c' ], [ 'b', 'd', 'a', 'e', 'f' ];
var result = list.reduce((acc, curr) => acc.concat(curr), []);
```
Keep in mind that this approach is less efficient and more verbose than the `lodash union` or `Set from flatten` approaches.

If you're looking for a pure JavaScript implementation without relying on Lodash or other libraries, consider using a Set-based approach:
```javascript
var list = [[ 'a', 'b', 'c' ], [ 'b', 'd', 'a', 'e', 'f' ];
var set = new Set();
list.forEach(arr => arr.forEach(el => set.add(el)));
```
This approach is more concise but may be slower and less readable than the other alternatives.

Related benchmarks:

Array immutable union: lodash union vs flatten and creating a new set (version: 0)

Comparing performance of: lodash union vs Set from flatten

Created: 4 years ago by: Guest

Jump to the latest result

lodash union

Set from flatten

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):