Benchmark: Lodash "unionWith" "unionBy" "uniqBy" 5

HTML Preparation code:

<script src='https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js'></script>

Script Preparation code:

var users = [
  { 'name': 'barney',  'age': 36 },
  { 'name': 'pebbles', 'age': 5 }
];

var newUsers = [
  { 'name': 'fred',    'age': 40 },
  { 'name': 'barney',  'age': 36 },
  { 'name': 'pebbles', 'age': 2 }
];

for(let i = 0; i < 2000; i++) {
  var newUser = { 'name': 'user_' + i, 'age': Math.floor(Math.random() * i) };
  newUsers.push(newUser);
}

Tests:

uniqWith
const unionUsers1 = _.uniqWith(newUsers.concat(users), _.isEqual);
unionBy
const unionUsers2 = _.unionBy(newUsers, users, 'name');
unionWith2
const unionUsers1 = _.uniqBy(newUsers.concat(users), 'name');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
uniqWith
unionBy
unionWith2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Browser/OS: Chrome 123 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
uniqWith	2.0 Ops/sec
unionBy	9017.0 Ops/sec
unionWith2	9565.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript microbenchmarks can be an intriguing topic.

**Overview**

The provided benchmark measures the execution time of three different methods for merging and processing arrays of objects using the Lodash library:

1. `uniqBy` (Union By): Merges two arrays and returns a new array with unique elements based on the specified property.
2. `unionWith` (Union With): Merges two arrays and returns a new array with all elements, using a custom function to determine uniqueness.
3. `uniqBy` alternative: Similar to `uniqBy`, but uses an alternative implementation.

**Description of each approach**

### 1. `uniqBy` (Union By)

* **Purpose:** Merges two arrays and returns a new array with unique elements based on the specified property (`'name'` in this case).
* **Functionality:** `_unionBy` iterates through both arrays, checks for uniqueness using `_.isEqual`, and adds unique elements to the result.
* **Pros:**
	+ Efficient implementation of union-by-based merging.
	+ Simplifies code by using a single function for all operations.
* **Cons:**
	+ May not perform well with large datasets due to the need to check for equality between elements.
	+ Uses `_.isEqual` which can be slow if used on non-primitive values.

### 2. `unionWith` (Union With)

* **Purpose:** Merges two arrays and returns a new array with all elements, using a custom function (`_.isEqual`) to determine uniqueness.
* **Functionality:** `_unionWith` iterates through both arrays, checks for uniqueness using the custom function, and adds unique elements to the result.
* **Pros:**
	+ Flexibility allows users to customize the uniqueness check using their own function.
	+ Can handle large datasets efficiently if the custom function is optimized.
* **Cons:**
	+ Requires a custom implementation of the uniqueness check, which can be error-prone.
	+ May not be as efficient as `uniqBy` due to the need for an additional function.

### 3. Alternative `uniqBy`

* **Purpose:** Similar to `uniqBy`, but uses an alternative implementation (no specific details provided).
* **Pros:**
	+ Possibly optimized for performance compared to the original `uniqBy`.
	+ May have other advantages over the standard implementation.
* **Cons:**
	+ No clear information on how it differs from the standard `uniqBy`.

**Library usage**

The benchmark uses the Lodash library, which provides various utility functions, including:

* `_unionBy`: Merges two arrays and returns a new array with unique elements based on the specified property.
* `_unionWith`: Merges two arrays and returns a new array with all elements, using a custom function to determine uniqueness.

**Special JavaScript features**

The benchmark does not specifically mention any special JavaScript features or syntax. However, it assumes that the user has access to modern JavaScript environments and Lodash library versions.

**Other alternatives**

If you need to merge arrays in a different way or require more flexibility in your uniqueness check, you can consider using other libraries like `lodash.merge` or implementing custom array merging functions.

Related benchmarks:

Lodash "unionWith" "unionBy" "uniqBy" 5 (version: 0)

Comparing performance of: uniqWith vs unionBy vs unionWith2

Created: 3 years ago by: Guest

Jump to the latest result

uniqWith

unionBy

unionWith2

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):