Benchmark: Regex vs 2 x indexOf

HTML Preparation code:

<div></div>

Script Preparation code:

window.regex = /^\/start\/\d+\/end/;
window.matchStart = 'start';
window.matchEnd = '/end';
var data = window.data = [];
var TOTAL_STRINGS = window.TOTAL_STRINGS = 100000;

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

function makeRandomString(len) {
  var text = "/start/";
  for( var i=0; i < len; i++ ) {
    text += (1 + getRandomInt(9));
  }
  text += "/end";
  return text;
}

while (data.length < TOTAL_STRINGS) {
  data.push(makeRandomString(getRandomInt(8)));
}

Tests:

Regex
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var regex = window.regex; while (x < TOTAL_STRINGS) { const str = data[x]; regex.test(str); x += 1; }
2 x indexOf
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var matchStart = window.matchStart; var matchEnd = window.matchEnd; while (x < TOTAL_STRINGS) { const str = data[x]; (str.indexOf(matchStart) === 1) && (str.indexOf(matchEnd) === str.length - 4); x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
2 x indexOf

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.

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

**Benchmark Definition**

The benchmark compares two approaches for identifying a specific URL string format in JavaScript:

1. **Regex (Regular Expression) match**: The `window.regex` variable contains a regular expression pattern (`/start\/\d+\/end/`) that matches the desired URL format.
2. **2 x indexOf**: This approach uses two separate `indexOf` calls to check if the string starts with `/start/` and ends with `/end/`. Specifically, it checks:
	* `(str.indexOf(matchStart) === 1)` ensures the string starts with `/start/`.
	* `(str.indexOf(matchEnd) === str.length - 4)` ensures the string ends with `/end/`.

**Options Compared**

The benchmark compares the performance of two approaches:

1. **Regex**: Uses a single regular expression pattern to match the entire URL format.
2. **2 x indexOf**: Uses two separate `indexOf` calls to check for the start and end conditions.

**Pros and Cons**

* **Regex**:
	+ Pros: Efficiently matches the entire URL format in a single operation.
	+ Cons: Can be slower if the pattern is complex or requires extensive processing.
* **2 x indexOf**: Pros: Simple, easy to understand, and may be faster for small inputs. Cons: Requires two separate calls, which can lead to additional overhead.

**Library/Functionality Used**

The benchmark uses JavaScript's built-in `indexOf` function, which searches for a specified value in a string and returns the index of that value if it is found.

**Special JS Feature/Syntax**

None are explicitly mentioned or utilized in this benchmark. The focus is on comparing two straightforward approaches using standard JavaScript functions.

**Other Alternatives**

If you want to compare these approaches with alternative methods, here are some options:

1. **Using a library like RegExp**: While the benchmark already uses a regular expression pattern, exploring other libraries or implementations (e.g., `RegExp` in Node.js) might reveal performance differences.
2. **String matching using techniques like Knuth-Morris-Pratt (KMP)**: This algorithm is optimized for searching substrings within larger strings and could potentially outperform the simple `indexOf` approach used here.
3. **Using a more efficient regular expression engine**: Some JavaScript engines, like V8 in Chrome, have built-in support for faster regular expressions or offer optimization options that can improve performance.

Keep in mind that these alternative approaches might not directly apply to this specific benchmark, but exploring them could provide additional insights into string matching and search optimizations.

Related benchmarks:

Regex vs 2 x indexOf (version: 0)

Compare if identifying a URL string to be a format of /start/1234/end is faster with regex match or indexOf at start and end

Comparing performance of: Regex vs 2 x indexOf

Created: 3 years ago by: Registered User

Jump to the latest result

Regex

2 x indexOf

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):