Benchmark: Measure date regex

Tests:

Date regex
const date = new Date(); const regexISO8601 = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/; regexISO8601.test(date.toString()); date.toString();
Date regex 2
const date = new Date(); const regexISO8601 = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/; regexISO8601.test(date.toString()); date.toString();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Date regex
Date regex 2

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 27 days ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON focuses on testing the performance of regular expressions (regex) used to validate ISO 8601 date-time strings in JavaScript. Here's a breakdown of the elements in the benchmark, as well as an analysis of the testing approach.

### What is Tested

The benchmarks are evaluating the effectiveness of a regex pattern that matches ISO 8601 date-time formats. ISO 8601 is a widely used format that represents date and time in a consistent way, generally following the pattern: `YYYY-MM-DDTHH:MM:SS.sssZ`.

The tests compare two identical implementations, named "Date regex" and "Date regex 2". Both utilize the same regex pattern and JavaScript method for executing the test.

**Benchmark Definition**:
- The regex in question is: 
  ```javascript
  /^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.\\d{3}Z$/
  ```
  This regex checks that the string is structured correctly with exactly four digits for the year, followed by a hyphen, two digits for the month, another hyphen, two digits for the day, the letter 'T', two digits for the hours, a colon, two digits for the minutes, another colon, two digits for the seconds, a period, three digits for milliseconds, and finally the letter 'Z'.

### Options Compared

1. **Implementation Consistency**:
    - Both test cases use identical code snippets, which measure the performance of the regex match operation on the string representation of a JavaScript `Date` object. Hence, there are no different implementation approaches to compare in this benchmark; both cases are essentially the same.

### Pros and Cons of Regex for Date Validation

**Pros**:
- **Conciseness**: Regular expressions provide a compact and expressive way to validate string formats.
- **Performance**: If implemented efficiently, regex can quickly determine string compliance with the specified pattern.

**Cons**:
- **Complexity**: Regex can become complex and difficult to read or maintain for more intricate date formats.
- **Edge Cases**: While regex can validate the format, it does not handle logical date validation (e.g., February 30th would pass the regex check but is an invalid date).

### Other Considerations

- **Performance Variability**: The benchmark results indicate high execution speeds (around 900,000 executions per second for both tests) on the tested environment, showing that regex operations are generally performant in the context of modern JavaScript engines.
- **Environment**: The tests are run in Chrome 129 on macOS, which can influence execution results due to JavaScript engine optimizations, so benchmarking may yield different results on different browsers/environments.

### Alternative Approaches for Date Validation

1. **Native Date Object**: Instead of regex, you could create `Date` objects using valid ISO 8601 strings and check their validity by ensuring they do not produce `NaN`:
   ```javascript
   const date = new Date(dateString);
   const isValid = !isNaN(date);
   ```
   *Pros*: Leverage native JavaScript date handling; easier and less error-prone.
   *Cons*: More verbose and involves instantiation of `Date` objects.

2. **Libraries**: Use libraries such as **date-fns** or **moment.js** for date handling and validation:
   - **date-fns** offers a modular approach for date manipulation, providing concise APIs for validation.
   - **moment.js** (though now in maintenance mode) represents a powerful library that simplifies date handling but comes with a larger footprint.
   *Pros*: Enhanced functionality and robust error handling; good for complex date operations.
   *Cons*: Additional dependencies and can increase bundle size.

By understanding the points above, software engineers can make more informed decisions when choosing methods for date validation in their applications, whether through simple regex, leveraging the native Date object, or utilizing external libraries.

Latest run results:

Run details: (Test run date: 28 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36

Browser/OS: Chrome 129 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Date regex	902846.3 Ops/sec
Date regex 2	903534.7 Ops/sec

Related benchmarks:

Measure date regex (version: 0)

Comparing performance of: Date regex vs Date regex 2

Created: 28 days ago by: Guest

Jump to the latest result

Date regex

Date regex 2

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 27 days ago):