Benchmark: Test endsWith vs regex

Script Preparation code:

var regex = /[hH]ash$/;
var str = 'signingSides.signatures.hash';

Tests:

regex
regex.test(str);
ends
str.endsWith('hash') || str.endsWith('Hash')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex
ends

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in this JavaScript microbenchmark.

The benchmark compares two approaches for checking if a string ends with the substring 'hash' or 'Hash': using a regular expression (`regex.test(str)`) versus using the `endsWith` method (a built-in JavaScript method).

**Regular Expression Approach:**

In this approach, a regular expression is created to match any string that ends with 'hash'. The regex is defined as `/[hH]ash$/`. This pattern checks for either 'h' or 'H', followed by the substring 'ash'.

**Pros:**

1. **Flexibility**: Regular expressions can be used to check for various patterns and edge cases, making them a powerful tool.
2. **Performance**: In general, regex is optimized for performance in JavaScript engines.

**Cons:**

1. **Complexity**: Regex patterns can become complex and difficult to read and maintain, especially for non-experts.
2. **Overhead**: Creating a regex object requires some overhead, which might impact performance in certain situations.

**Built-in `endsWith` Method Approach:**

This approach uses the built-in `endsWith` method, which is part of the JavaScript standard library. This method takes two arguments: the string to check and the substring to look for at the end.

Pros:

1. **Simplicity**: The `endsWith` method is easy to understand and use.
2. **Performance**: Built-in methods like `endsWith` are optimized for performance in JavaScript engines.

Cons:

1. **Limited control**: With built-in methods, you have limited control over the exact behavior or edge cases.

**Other Considerations:**

1. **Case sensitivity**: Both approaches will treat 'hash' and 'Hash' as different substrings.
2. **Edge cases**: The regular expression approach might handle more edge cases than the `endsWith` method, especially if the input string is not what you expect.

**Library/Functionality Used:**

The `regex` object is created using a simple regex pattern. No other libraries are used in this benchmark.

**Special JS Feature/Syntax:**

There's no special JavaScript feature or syntax being tested here; it's a straightforward comparison of two approaches.

**Other Alternatives:**

If you need to check if a string ends with a specific substring, you might consider using the `substr` method and comparing the result to 0:

```javascript
str.length > str.indexOf(substring) + substring.length;
```

However, this approach is less efficient and more error-prone than the built-in `endsWith` method.

Keep in mind that this benchmark is likely comparing performance aspects of these approaches rather than their correctness or usability.

Related benchmarks:

Test endsWith vs regex (version: 1)

Comparing performance of: regex vs ends

Created: 3 years ago by: Registered User

Jump to the latest result

regex

ends

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):