Benchmark: Array immutable union: lodash union vs ...new Set vs uniq

HTML Preparation code:

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

Tests:

lodash union
var a = [ 'a', 'b', 'c' ]; var b = [ 'b', 'd', 'a', 'e', 'f' ]; var c = _.union(a, b);
new Set
var a = [ 'a', 'b', 'c' ]; var b = [ 'b', 'd', 'a', 'e', 'f' ]; var c = [...new Set([...a ,...b])];
lodash uniq spread
var a = [ 'a', 'b', 'c' ]; var b = [ 'b', 'd', 'a', 'e', 'f' ]; var c = _.uniq([...a, ...b]);

Historical Performance Data aggregated from 26 community runs

Desktop Results:

Chrome 26 runs

lodash uniq spread

5.9M/s

new Set

4.4M/s

lodash union

3.8M/s

Fastest: lodash uniq spread (1.6x faster)

View exact numbers

✓ lodash uniq spread: 5,882,764 ops/sec
• new Set: 4,393,089 ops/sec
• lodash union: 3,781,345 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash union
new Set
lodash uniq spread

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0

Browser/OS: Firefox 146 on Windows

View result in a separate tab

lodash uniq spread

9.9M/s

lodash union

6.5M/s

new Set

4.7M/s

View exact numbers

Test name	Executions per second
✓ lodash uniq spread	9,907,050 Ops/sec
lodash union	6,503,472 Ops/sec
new Set	4,691,168 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**Overview**

The benchmark is designed to compare the performance of three approaches for removing duplicates from an array: Lodash's `union` function, creating a new Set using the spread operator (`new Set([...a, ...b])`), and Lodash's `uniq` function with the spread operator (`_.uniq([...a, ...b])`). The benchmark aims to determine which approach is the most efficient.

**Test Cases**

There are three test cases:

1. **Lodash union**: This test case uses Lodash's `union` function to combine two arrays and remove duplicates.
2. **New Set**: This test case creates a new Set by spreading two arrays together, effectively removing duplicates.
3. **Lodash uniq spread**: This test case uses Lodash's `uniq` function with the spread operator to remove duplicates from an array.

**Options Compared**

The benchmark is comparing three options:

1. Lodash's `union` function
2. Creating a new Set using the spread operator (`new Set([...a, ...b])`)
3. Lodash's `uniq` function with the spread operator (`_.uniq([...a, ...b])`)

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Lodash union**:
	* Pros: Easy to use, well-tested library.
	* Cons: May have a performance overhead due to the complexity of the function.
2. **New Set**:
	* Pros: Simple, efficient, and widely supported.
	* Cons: Requires modern JavaScript versions (ECMAScript 2015+) and may not work in older browsers.
3. **Lodash uniq spread**:
	* Pros: Simple, efficient, and well-tested library.
	* Cons: May have a performance overhead due to the spread operator.

**Libraries**

Two libraries are used in this benchmark:

1. Lodash (version 4.17.5): A popular JavaScript utility library that provides various functions for data manipulation and more.
2. No other libraries are used in the test cases.

**Special JS Features or Syntax**

The benchmark uses modern JavaScript features, such as:

1. Spread operator (`[...a, ...b]`)
2. Rest parameters ( implicit, not explicit)
3. ES6 classes (not used explicitly, but JavaScript version is 2015+, which requires ES6 compatibility)

Overall, the benchmark provides a good comparison of three approaches for removing duplicates from an array and highlights the pros and cons of each approach.

**Other Alternatives**

If you're looking for alternative ways to remove duplicates from an array, here are some options:

1. Use `Array.prototype.filter()`: `a.filter((x, i) => a.indexOf(x) === i)`
2. Use `Array.prototype.reduce()`: `a.reduce((acc, x) => acc.includes(x) ? acc : [...acc, x])`
3. Use `Set` objects: `new Set(a).size`
4. Use `JSON.parse(JSON.stringify([...a, ...b]))`: This approach assumes that the elements in the array are JSON serializable.

Keep in mind that each of these alternatives has its own trade-offs and may not be as efficient or easy to use as the approaches tested in this benchmark.

Array immutable union: lodash union vs ...new Set vs uniq (version: 0)

Comparing performance of: `lodash union vs new Set vs lodash uniq spread`

Created: 4 years ago by: Guest

Go to the latest result

lodash union

new Set

lodash uniq spread

Historical Performance Data aggregated from 26 community runs

Desktop Results:

Chrome 26 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Array immutable union: lodash union vs ...new Set vs uniq (version: 0)

Comparing performance of: lodash union vs new Set vs lodash uniq spread

Created: 4 years ago by: Guest

Go to the latest result

lodash union

new Set

lodash uniq spread

Historical Performance Data aggregated from 26 community runs

Desktop Results:

Chrome 26 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `lodash union vs new Set vs lodash uniq spread`