Benchmark: RegEx vs For Loop ... no bullshit

HTML Preparation code:

var string = ")odas4gsdfsdfpassw";

Script Preparation code:

var string = ")odas4gsdfsdfpassw";

Tests:

RegEx
let isPasswordValid = false; const number = new RegExp('(?=.*[0-9])'); isPasswordValid = number.test(string);
For Loop
let isPasswordValid = false; for (let i = 0; i < string.length; i++) { let code = string.charCodeAt(i); if (code >= 48 && code <= 57) { isPasswordValid = true; break; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
RegEx
For Loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:148.0) Gecko/20100101 Firefox/148.0

Browser/OS: Firefox 148 on Windows

View result in a separate tab

Test name	Executions per second
RegEx	7184662.0 Ops/sec
For Loop	41189748.0 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 is defined by two JavaScript microbenchmarks that compare the performance of regular expressions (RegEx) to traditional for loops in validating if a string contains at least one digit.

**Test Cases**

There are two test cases:

1. **RegEx**: This test case uses a RegEx pattern to check if the string contains at least one digit.
```javascript
const number = new RegExp('(?=.*[0-9])');
isPasswordValid = number.test(string);
```
The `(?=.*[0-9])` pattern is a positive lookahead assertion that checks if the string contains at least one digit (represented by the `[0-9]` character class).

2. **For Loop**: This test case uses a traditional for loop to iterate through each character in the string and check if it's a digit.
```javascript
for (let i = 0; i < string.length; i++) {
    let code = string.charCodeAt(i);
    if (code >= 48 && code <= 57) {
        isPasswordValid = true;
        break;
    }
}
```
The `charCodeAt()` method returns the Unicode code point of each character in the string, and the `if` statement checks if it's a digit by comparing the code point to the ASCII range for digits (48-57).

**Library**

There is no library explicitly mentioned in this benchmark. However, the RegEx pattern uses the JavaScript String API.

**Special JS Feature/Syntax**

The RegEx pattern uses the positive lookahead assertion (`(?=...)`) which is a feature of modern JavaScript regex engines that allows us to check if a string matches a certain condition without consuming any characters.

**Pros and Cons**

Here are some pros and cons of each approach:

* **RegEx**:
	+ Pros: Concise, expressive, and efficient for most cases.
	+ Cons: Can be slow for very large strings or complex patterns, and may not be supported by older browsers.
* **For Loop**:
	+ Pros: Simple, reliable, and widely supported across browsers.
	+ Cons: May be slower than RegEx for certain use cases.

**Other Alternatives**

If the benchmark were to compare performance with other approaches, some alternatives could include:

* Using a more efficient algorithm, such as using a Boyer-Moore or Knuth-Morris-Pratt string matching algorithm.
* Using a library like `regex- optimize` which provides optimized regex engines for JavaScript.
* Using a JavaScript engine that supports Just-In-Time (JIT) compilation, which can provide significant performance improvements.

**Considerations**

When choosing between RegEx and a traditional for loop, consider the following factors:

* Readability and maintainability: RegEx patterns can be concise but also harder to read and understand than traditional loops.
* Performance: RegEx patterns are generally faster than traditional loops, but this may depend on the specific use case and string size.
* Browser support: RegEx patterns may not work in older browsers or with specific browser configurations.

Related benchmarks:

RegEx vs For Loop ... no bullshit (version: 0)

-

Comparing performance of: RegEx vs For Loop

Created: 5 years ago by: Guest

Jump to the latest result

RegEx

For Loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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