Benchmark: Unnecessary non-capturing groups

Script Preparation code:

var loremString = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."

Tests:

unneededNonCaptureRE
/(?:z)+/.exec(loremString)
noNonCaptureRE
/z+/.exec(loremString)
anotherUnneededNonCapture
/lab(?:o)rum/.exec(loremString)
anotherNoNonCapture
/laborum/.exec(loremString)
indexOf
loremString.indexOf('laborum')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
unneededNonCaptureRE
noNonCaptureRE
anotherUnneededNonCapture
anotherNoNonCapture
indexOf

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/113.0

Browser/OS: Firefox 113 on Windows

View result in a separate tab

Test name	Executions per second
unneededNonCaptureRE	4288846.5 Ops/sec
noNonCaptureRE	4287936.0 Ops/sec
anotherUnneededNonCapture	5368798.5 Ops/sec
anotherNoNonCapture	7372564.5 Ops/sec
indexOf	914122432.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

The provided JSON represents a benchmark test case for measuring the performance of different approaches to search for substrings in a string using regular expressions (regex) or built-in string methods. Here's what we'll cover:

**Benchmark Definition:**

The benchmark is named "Unnecessary non-capturing groups". The problem it addresses is whether adding unnecessary parentheses around a non-capturing group (`(?:`) affects performance compared to not including them at all.

**Script Preparation Code:**
```javascript
var loremString = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
```
This code prepares a sample string `loremString` for testing.

**Html Preparation Code:**
```javascript
null
```
There's no HTML preparation code provided, which means the test is purely JavaScript-based.

**Individual Test Cases:**

The benchmark consists of five test cases:

1. `/z+/.exec(loremString)`: Using regex with a non-capturing group (`?:`) and `z` (zero-width match) character.
2. `/z+/.exec(loremString)`: Same as above, but without the unnecessary parentheses around the non-capturing group.
3. `/lab(?:o)rum/.exec(loremString)`: Using regex with an unnecessary non-capturing group (`(?:`) and a substring search.
4. `/laborum/.exec(loremString)`: Same as above, but without the unnecessary parentheses.
5. `loremString.indexOf('laborum')`: Using the built-in `indexOf` method of the string.

**Performance Comparison:**

The benchmark tests the performance of each approach by measuring the number of executions per second (ExecutionsPerSecond) on a specific browser version and platform.

**Options Compared:**

* Regex with non-capturing group (`(?:`) and `z` character vs. without it.
* Regex with unnecessary parentheses around a non-capturing group vs. without them.

**Pros and Cons:**

1. **Regex with non-capturing group (`(?:`) and `z` character:**
	* Pros:
		+ Might be faster due to the `z` character, which can match zero characters.
		+ Can handle zero-width matches.
	* Cons:
		+ Unnecessary parentheses might affect performance.
2. **Regex without non-capturing group (`(?:`) and `z` character:**
	* Pros:
		+ No unnecessary parentheses, potentially faster.
	* Cons:
		+ Might not perform as well with zero-width matches.

**Other Considerations:**

* The test cases are designed to be simple and focused on the specific issue of unnecessary non-capturing groups. More comprehensive benchmarking might require additional test cases.
* The use of a sample string `loremString` makes it easy to understand the testing scenario, but might not represent real-world usage.

**Alternatives:**

If you need to benchmark similar scenarios or want to explore other optimization techniques, consider:

1. Using more realistic input data and/or edge cases.
2. Adding test cases for other optimization techniques, such as caching, memoization, or parallel processing.
3. Experimenting with different regex flavors (e.g., PCRE) or JavaScript engines (e.g., V8).
4. Investigating performance differences between built-in string methods (like `indexOf`) and regex.

Keep in mind that microbenchmarking can be complex, and results may vary depending on specific hardware, software, and environment configurations.

Related benchmarks:

Unnecessary non-capturing groups (version: 0)

https://stackoverflow.com/questions/45291700/javascript-regex-non-capture-faster-than-no-parenthesis-at-all

Comparing performance of: unneededNonCaptureRE vs noNonCaptureRE vs anotherUnneededNonCapture vs anotherNoNonCapture vs indexOf

Created: 7 years ago by: Guest

Jump to the latest result

unneededNonCaptureRE

noNonCaptureRE

anotherUnneededNonCapture

anotherNoNonCapture

indexOf

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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