Benchmark: Define Regex inline vs not.

Script Preparation code:

ONE_REGEX = /^(?!.* $\s)[\w *()[\]'"/.&–-]+$/gm

Tests:

inline defined
(function (text) { const SOME_OTHER_REGEX = /^(?!.* $\s)[\w *()[\]'"/.&–-]+$/gm; SOME_OTHER_REGEX.test(text); })('bla')
using one_regex
(function (text) { ONE_REGEX.test(text); })('bla')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
inline defined
using one_regex

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**

The benchmark measures two approaches to defining regular expressions (regex) in JavaScript:

1. **Inline defined**: The regex is defined directly inside the function body, within the parentheses that contain the `test` method call.
2. **Using one_regex**: A separate variable, `ONE_REGEX`, is defined outside the function and used within the function.

**Options Compared**

The benchmark compares the performance of two approaches:

* Inline definition of regex
* Using a separate variable to define regex

**Pros and Cons of Each Approach**

1. **Inline Definition**
	* Pros:
		+ Can be more concise and easier to read, as the regex is defined directly where it's used.
		+ Reduces the need for additional variables or memory allocation.
	* Cons:
		+ May lead to larger function sizes due to the inline definition of the regex.
		+ Can make debugging and maintenance more difficult, as the regex is deeply embedded in the code.
2. **Using one_regex**
	* Pros:
		+ Separates the regex from the rest of the function body, making it easier to manage and maintain.
		+ Can improve readability by explicitly defining the regex outside the function.
	* Cons:
		+ Requires an additional variable declaration, which can increase memory usage.
		+ May require more overhead due to the creation and storage of the regex object.

**Library and Purpose**

The `RegExp` class is used in both test cases. The `RegExp` constructor takes two arguments: a pattern string and an optional flags value. In this benchmark, the flags value is set to `'g'`, which enables global matching (i.e., matching all occurrences of the regex in the input string).

**Special JS Feature/Syntax**

None are mentioned or used explicitly in the provided test cases.

**Other Alternatives**

If you wanted to explore alternative approaches, consider these options:

1. **String.prototype.replace()**: Instead of using `RegExp.test()` directly, you could use `String.prototype.replace()` with a callback function that takes a match array as an argument.
2. **Use a library like Lodash's `regex` helper**: If you need to perform complex regex operations frequently, consider using a utility library like Lodash, which provides a range of regex helpers.

**Benchmark Result**

The benchmark results show the performance difference between the two approaches. The inline defined approach outperforms the "using one_regex" approach by a significant margin, likely due to the overhead of creating and storing the `ONE_REGEX` variable.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36

Browser/OS: Chrome 71 on Mac OS X 10.14.2

View result in a separate tab

Test name	Executions per second
inline defined	19693694.0 Ops/sec
using one_regex	4122908.8 Ops/sec

Related benchmarks:

Define Regex inline vs not. (version: 0)

Comparing performance of: inline defined vs using one_regex

Created: 5 years ago by: Guest

Jump to the latest result

inline defined

using one_regex

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):