Benchmark: Lodash vs Javascript Regexp Intersection (Fix)

HTML Preparation code:

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

Script Preparation code:

var first = _.range(0, 10000, 4);
var second = _.range(0, 10000, 2);

Tests:

Javascript Regexp Intersection
const firstRegex = new RegExp(`^(${first.join('|')})$`, "g") second.filter((s) => firstRegex.test(s))
Lodash Intersection
_.intersection(first, second)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Javascript Regexp Intersection
Lodash Intersection

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided JSON to understand what's being tested and the pros and cons of different approaches.

**Benchmark Definition**

The benchmark is comparing two functions: `_.intersection` from Lodash library and `filter` with regular expressions (`firstRegex.test`) on an array of numbers.

**Script Preparation Code**
```javascript
var first = _.range(0, 10000, 4);
var second = _.range(0, 10000, 2);
```
This code creates two arrays: `first` and `second`. The `_range` function generates an array of numbers with the specified step size.

**Html Preparation Code**
```html
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
```
This line includes the Lodash library, which provides the `_.intersection` function.

**Individual Test Cases**

There are two test cases:

1. **Javascript Regexp Intersection**
```javascript
const firstRegex = new RegExp(`^(${first.join('|')})$`, "g");
second.filter((s) => firstRegex.test(s));
```
This code creates a regular expression (`firstRegex`) that matches any number in the `first` array, and then filters the `second` array to only include numbers that match this regex.

2. **Lodash Intersection**
```javascript
_.intersection(first, second);
```
This code uses Lodash's `_.intersection` function to find the intersection of the two arrays.

**Library**

The library used is Lodash, which provides a set of utility functions for working with arrays and other data structures.

**Pros and Cons**

1. **Regular Expressions (Regex)**:
	* Pros: can be flexible and powerful for matching complex patterns.
	* Cons: can be slow for large datasets due to the overhead of creating and compiling regex objects.
2. **Lodash's `_intersection` function**:
	* Pros: optimized for performance and provides a simple, concise way to find intersections.
	* Cons: may not be as flexible as using regular expressions directly.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax used in this benchmark that requires explanation.

**Other Alternatives**

1. **Using `filter` with `every`**: Instead of using a regex, you could use the `every` method to filter the second array:
```javascript
second.filter((s) => first.every((f) => f === s));
```
This approach can be faster than using regular expressions, but may not provide the same level of flexibility.

2. **Using `Set` data structure**: You could convert both arrays to sets and use the `intersection` method to find their intersection:
```javascript
const firstSet = new Set(first);
const secondSet = new Set(second);
const intersection = [...firstSet].filter((x) => secondSet.has(x));
```
This approach can be faster than using Lodash's `_intersection` function, but may require more memory.

Overall, the benchmark highlights the trade-offs between using regular expressions, optimized library functions (like Lodash's `_intersection`), and other approaches for finding intersections in large datasets.

Related benchmarks:

Lodash vs Javascript Regexp Intersection (Fix) (version: 1)

Comparing performance of: Javascript Regexp Intersection vs Lodash Intersection

Created: 3 years ago by: Registered User

Jump to the latest result

Javascript Regexp Intersection

Lodash Intersection

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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