Benchmark: endsWith() vs regex

Tests:

endsWith
'Hello World'.endsWith('rld')
regex
/rld$/.test('Hello World')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
endsWith
regex

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested.

**Overview**

The benchmark compares two approaches to check if a string ends with a specific substring: the `endsWith()` method and regular expressions (regex).

**Options compared**

There are two options being compared:

1. **endsWith() method**: This method checks if a string ends with a specified value.
2. **Regular Expressions (regex)**: Specifically, the `/rld$/` pattern is used to match strings that end with the substring "rld".

**Pros and Cons of each approach**

* `endsWith()` method:
	+ Pros:
		- More readable and concise syntax.
		- Can be faster since it's a native JavaScript method.
	+ Cons:
		- May not work as expected for non-English characters, as it relies on Unicode normalization.
		- May have performance issues if the string is very long or if the substring is not found.
* Regex (`/rld$/` pattern):
	+ Pros:
		- Can handle any character set and can be more flexible than `endsWith()`.
		- Performance is generally better for longer strings or when searching for a specific pattern.
	+ Cons:
		- More complex syntax, which may lead to readability issues.
		- May require additional setup (e.g., Unicode normalization) if used with non-English characters.

**Library and Purpose**

In this benchmark, no library is explicitly mentioned. However, the use of regex implies that JavaScript's built-in `RegExp` object or a similar implementation is being utilized.

**Special JS feature or syntax**

There are no special JS features or syntaxes mentioned in this benchmark. The focus is on comparing two common string manipulation approaches.

**Other alternatives**

Other alternatives for checking if a string ends with a specific substring include:

* Using the `String.prototype.slice()` method with a negative index to extract the ending part of the string.
* Utilizing a library like Lodash's `endsWith()` function, which provides a more robust implementation of this functionality.
* Implementing custom logic using bitwise operations or other algorithms optimized for performance.

**Benchmark preparation code**

Since no specific preparation code is provided in the benchmark definition JSON, it's likely that the test cases are designed to be run with minimal setup. In practice, you would typically include code to:

* Define the string and substring being tested.
* Prepare any necessary data structures or variables.
* Set up the testing environment (e.g., executing a function that runs the tests).

**Individual test cases**

The provided benchmark definition includes two individual test cases:

1. `endsWith`: Tests if "Hello World" ends with the substring "rld".
2. `regex`: Tests if "Hello World" matches the regex pattern `/rld$/.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36 Edg/80.0.361.111

Browser/OS: Chrome 80 on Windows

View result in a separate tab

Test name	Executions per second
endsWith	45069192.0 Ops/sec
regex	30388990.0 Ops/sec

Related benchmarks:

endsWith() vs regex (version: 0)

Comparing performance of: endsWith vs regex

Created: 4 years ago by: Guest

Jump to the latest result

endsWith

regex

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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