Benchmark: union vs concat+uniq

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 AA = [[1, 2, 3, 4, 5],[1, 3, 3, 4, 5],[1, 8, 3, 4, 9],[1, 4, 3, 4, 5],[1, 1, 3, 4, 5],[1, 6, 7, 4, 5],[1, 7, 7, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5],[1, 4, 3, 4, 5]]

Tests:

concat+uniq
var a = AA.reduce((accum, x) => { return accum.concat(x); }) var b = _.uniq(a)
union
var a = AA.reduce((accum, x) => { return _.union(accum, x); }) var b = a;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
concat+uniq
union

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and explain what's being tested, along with the pros and cons of each approach.

**Benchmark Definition**

The test case compares two approaches to unionize an array:

1. `concat+uniq`: This approach concatenates all sub-arrays using the `reduce()` method and then removes duplicates from the resulting array using the `_` (Lodash) library's `uniq()` function.
2. `union`: This approach directly uses the `_.union()` function to unionize all sub-arrays in a single call.

**Test Case 1: `concat+uniq`**

The test case prepares an input array `AA` with 13 sub-arrays, each containing some unique elements.

To create the benchmark:

* The script preparation code initializes the input array `AA`.
* The HTML preparation code includes the Lodash library via a CDN.

When run, this test case executes the following steps:
1. Reduces the input array using `reduce()` and concatenates all sub-arrays.
2. Removes duplicates from the resulting array using `_uniq()`.
3. Assigns the results to variables `a` and `b`, respectively.

**Pros of `concat+uniq`**

* This approach is generally more efficient for small arrays or when working with a specific subset of data, as it allows for early removal of duplicates.
* It's also more intuitive for developers familiar with JavaScript's built-in `reduce()` method.

**Cons of `concat+uniq`**

* This approach requires two separate operations (concatenation and deduplication), which can be slower and less efficient than a single call to `_union()`.
* It may lead to temporary arrays that are not immediately garbage-collected, potentially causing memory issues for large datasets.

**Test Case 2: `union`**

The test case prepares the same input array `AA`.

To create the benchmark:

* The script preparation code initializes the input array `AA`.
* The HTML preparation code includes the Lodash library via a CDN.

When run, this test case executes a single call to `_union()` on the input array directly.

**Pros of `union`**

* This approach is generally more efficient and concise than the `concat+uniq` method.
* It avoids the overhead of two separate operations (concatenation and deduplication).

**Cons of `union`**

* This approach can be less intuitive for developers unfamiliar with Lodash's `_union()` function or may require additional setup to understand how it works.

**Other Considerations**

Both approaches assume that the input array is not empty and that all sub-arrays have at least one element. If this assumption is not met, additional error handling or edge-case checking may be necessary.

In terms of alternatives, other methods for unionizing arrays in JavaScript include:

* Using `Set` objects: This approach can be more concise but may lead to slower performance for large datasets due to the overhead of Set operations.
* Implementing a custom union function using `for...in` loops or recursion: These approaches are generally less efficient and more prone to errors than Lodash's `_union()` function.

Overall, the choice between `concat+uniq` and `union` depends on your specific use case, performance requirements, and personal preference.

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/69.0.3497.81 Chrome/69.0.3497.81 Safari/537.36

Browser/OS: Chromium 69 on Ubuntu

View result in a separate tab

Test name	Executions per second
concat+uniq	173362.3 Ops/sec
union	91227.9 Ops/sec

Related benchmarks:

union vs concat+uniq (version: 0)

Comparing performance of: concat+uniq vs union

Created: 6 years ago by: Guest

Jump to the latest result

concat+uniq

union

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):