Benchmark: regexp capturing group named vs indexed

Script Preparation code:

var includeRegexpNamed = /=include\((?<file>.+?)(?:\)|,\s*{(?<data>.+?)}\))/g;
var includeRegexpIndexed = /=include\((.+?)(?:\)|,\s*{(.+?)}\))/g;
var str = "qqqqqqq qqqqqqqq qqqqqqqqqqqqqq let res=include('./file.eta', { name: 'eta' }) qqqqqqq qqqqqqqq qqqqqqqqqqqqqq qqqqqqq";

Tests:

named group
var result = str.replaceAll(includeRegexpNamed, `=require($<file>)({...it, ...{$<data>}})`);
indexed group
var result = str.replaceAll(includeRegexpIndexed, `=require($1)({...it, ...{$2}})`);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
named group
indexed group

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36

Browser/OS: Chrome 132 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
named group	4607536.0 Ops/sec
indexed group	5255761.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark compares two approaches for replacing regular expressions in a string: one using named capture groups (`includeRegexpNamed`) and another using indexed capture groups (`includeRegexpIndexed`).

**Regular Expressions (Regex)**

In this context, a regex is used to match the string `str`, which contains placeholders that will be replaced with actual values. The regex pattern is:

`=require($<file>)({...it, ...{$<data>}})`

The `<file>` and `<data>` parts are placeholders for values that need to be included in the replacement.

**Named Capture Groups (`includeRegexpNamed`)**

In this approach, named capture groups are used. A named group is a regex feature that allows you to create a named reference to a capture group. In this case, `includeRegexpNamed` uses:

`=include\$(?<file>.+?)(?:\$|,\\s*{(?<data>.+?)}\\))/g`

Here, `<file>` and `<data>` are named capture groups (`(?<file>.+?)` and `(?<data>.+?)`, respectively). The `g` flag at the end makes the regex global.

When using named capture groups, the replacement string becomes:

`=require($<file>)({...it, ...{$<data>}})`

**Indexed Capture Groups (`includeRegexpIndexed`)**

In this approach, indexed capture groups are used. An indexed group is a regex feature that allows you to create an index-based reference to a capture group. In this case, `includeRegexpIndexed` uses:

`=include\$(.+?)(?:\$|,\\s*{(.+?)}\\))/g`

Here, `$<file>` and `$<data>` are indexed capture groups (`(.+?)` and `(.+?`, respectively). The `1` and `2` in the replacement string refer to these indices.

When using indexed capture groups, the replacement string becomes:

`=require($1)({...it, ...{$2}})``

**Options Compared**

The benchmark compares two options:

1. **Named Capture Groups (`includeRegexpNamed`)**: uses named reference for capturing groups.
	* Pros:
		+ Easier to read and maintain, as the capture group names are explicitly defined.
		+ Can be more readable and self-documenting.
	* Cons:
		+ May have performance overhead due to the added complexity of named captures.
2. **Indexed Capture Groups (`includeRegexpIndexed`)**: uses index-based reference for capturing groups.
	* Pros:
		+ Typically faster, as there's less overhead in parsing the indices.
		+ Can be more efficient in terms of execution speed.
	* Cons:
		+ Requires careful management of indices to avoid errors or unexpected behavior.

**Library Used**

In this benchmark, `include` is a built-in function for including files or data into the replacement string. Its purpose is to allow you to include values from external sources (files) into your regex pattern.

**Special JS Feature/Syntax**

This benchmark uses JavaScript's named and indexed capture groups features, which are specific to ECMAScript 2015+ syntax.

**Other Alternatives**

For replacing regex patterns in strings, there are other approaches and libraries available. Some alternatives include:

1. **String.prototype.replaceAll**: a built-in method for replacing substrings in a string.
2. **regex-replace**: a library for regular expression replacement in Node.js.
3. **replace**: a built-in function or a library like `lodash.replace` for replacing regex patterns.

These alternatives may have different performance characteristics, syntax, and usage compared to the named and indexed capture groups approach used in this benchmark.

Related benchmarks:

regexp capturing group named vs indexed (version: 0)

Comparing performance of: named group vs indexed group

Created: 2 years ago by: Guest

Jump to the latest result

named group

indexed group

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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