Benchmark: Set union methods

HTML Preparation code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/nanoid/4.0.1/index.browser.js" integrity="sha512-YFaQHp+hWX9CMeIMngYK23kSIWaYlgsswmzmIdEw/HcK/5NLhXY2MbT0wQB5DnUzjW1uky4quIHtksukqZGkMw==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

Script Preparation code:

const SET_SIZE = 1000;

var set1 = new Set()
var set2 = new Set()
while (i < SET_SIZE) {
    const nid = 'key:'+Math.random();
    set1.add(nid);
    if (i % 2 == 0) set2.add(nid);
    i++;
}
while (i < SET_SIZE / 2) {
    set2.add('key:'+Math.random());
}

Tests:

Spreading
const set3 = new Set([...set1, ...set2]); console.log(set3.size)
Set.forEach + Set.add
const set3 = new Set(set1); set2.forEach(el => set3.add(el)); console.log(set3.size)
Generators
const set3 = new Set(function*() { yield* set1; yield* set2; }()); console.log(set3.size)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spreading
Set.forEach + Set.add
Generators

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36

Browser/OS: Chrome 115 on Windows

View result in a separate tab

Test name	Executions per second
Spreading	15187.5 Ops/sec
Set.forEach + Set.add	13732.4 Ops/sec
Generators	9667.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and analyzed.

**Benchmark Overview**

The benchmark is designed to compare different methods for unionizing JavaScript Sets. A Set in JavaScript is an unordered collection of unique values. The benchmark aims to determine which method is most efficient for combining two Sets.

**Test Cases**

There are three test cases:

1. **Spreading**: This method uses the spread operator (`...`) to create a new Set from the elements of `set1` and `set2`.
```javascript
const set3 = new Set([...set1, ...set2]);
console.log(set3.size);
```
Pros: Simple and concise. This method is widely supported across modern browsers.

Cons: May not be as efficient as other methods for very large Sets due to the creation of a new array.

2. **Set.forEach + Set.add**: This method iterates over `set1` using `forEach` and adds each element to `set3` using `add`.
```javascript
const set3 = new Set(set1);
set2.forEach(el => set3.add(el));
console.log(set3.size);
```
Pros: Can be more efficient for large Sets because it avoids creating a temporary array.

Cons: May have higher overhead due to the iteration and function calls.

3. **Generators**: This method uses a generator function to yield elements from `set1` and `set2`, which are then added to `set3`.
```javascript
const set3 = new Set(function*() { yield* set1; yield* set2; }());
console.log(set3.size);
```
Pros: Can be more efficient for very large Sets because it avoids creating temporary arrays.

Cons: May have higher overhead due to the creation of a generator function and its associated computations.

**Library Used**

The benchmark uses the `nanoid` library, which generates random IDs. However, this library is not explicitly used in the test cases; instead, it's used for the browser's identification string (`RawUAString`) in the benchmark results.

**Special JavaScript Features or Syntax**

None of the methods use any special JavaScript features or syntax that would affect their performance.

**Alternatives**

Other alternatives for unionizing Sets include:

* Using the `Set.prototype.union()` method (not supported in older browsers).
* Using a library like `lodash.set` or `underscore.util.union`.
* Implementing a custom union function using bitwise operations or other techniques.

Keep in mind that the choice of method depends on the specific use case, performance requirements, and compatibility considerations.

Related benchmarks:

Set union methods (version: 0)

Different ways to union JS Sets

Comparing performance of: Spreading vs Set.forEach + Set.add vs Generators

Created: one year ago by: Guest

Jump to the latest result

Spreading

Set.forEach + Set.add

Generators

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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