Benchmark: RegEx defined inside vs outside Loop

Script Preparation code:

var string = "passw)odas4gsdfsdf";
var regex = /(?=.*[0-9])/

Tests:

inside
let isPasswordValid = /(?=.*[0-9])/.test(string);
outside
let isPasswordValid = regex.test(string);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
inside
outside

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Windows

View result in a separate tab

Test name	Executions per second
inside	16327090.0 Ops/sec
outside	17510948.0 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 benchmark and its test cases.

**Benchmark Definition**

The benchmark measures the performance of two approaches to create a regular expression (RegEx) object: defining it inside a loop versus defining it outside a loop.

**Options Compared**

Two options are compared:

1. **Inside Loop**: The RegEx pattern is defined inside a loop, which means it will be recreated on every iteration.
2. **Outside Loop**: The RegEx pattern is defined outside the loop, which means it will be created only once and reused for all iterations.

**Pros and Cons of Each Approach**

* **Inside Loop**:
	+ Pros: Can be useful in scenarios where the pattern needs to change frequently or dynamically.
	+ Cons: Creating a new object on every iteration can lead to performance overhead due to object creation, garbage collection, and potential cache misses.
* **Outside Loop**:
	+ Pros: Reduces object creation overhead and caching issues, as the RegEx object is only created once.
	+ Cons: If the pattern changes or needs to be updated frequently, it may not be efficient to reuse an existing object.

**Library Used**

In this benchmark, no specific library is used other than JavaScript's built-in `RegExp` object. The `RegExp` object is used to create and test RegEx patterns.

**Special JS Feature/Syntax (Not Applicable)**

There are no special features or syntax mentioned in the benchmark definition.

**Alternative Approaches**

Other approaches to defining RegEx patterns might include:

* Using a constructor function to create a new RegEx object on every iteration.
* Precompiling and caching RegEx objects for frequently used patterns.
* Using a string template engine like Handlebars to generate RegEx patterns dynamically.

However, these alternatives are not explicitly compared in this benchmark.

**Benchmark Preparation Code**

The provided script preparation code defines two variables: `string` and `regex`. The `regex` variable is assigned a RegEx pattern using the `/` character, which is the standard syntax for creating RegEx objects in JavaScript. The `string` variable contains a test string that will be used to validate the RegEx pattern.

The HTML preparation code is not provided in this example.

I hope this explanation helps software engineers understand the benchmark and its underlying concepts!

Related benchmarks:

RegEx defined inside vs outside Loop (version: 0)

Comparing performance of: inside vs outside

Created: one year ago by: Guest

Jump to the latest result

inside

outside

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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