Benchmark: OR JS Regex vs 2 .startsWith

HTML Preparation code:

<div></div>

Script Preparation code:

window.regexStart = /^(test|test2)/;
window.regexEnd = /test$/;
window.match = 'test';
window.match2 = 'test2';
window.matchLength = window.match.length;
var data = window.data = [];
const possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var TOTAL_STRINGS = window.TOTAL_STRINGS = 100000;

function getRandomInt(max) {
  return Math.floor(Math.random() * max);
}

function makeRandomString(len) {
  var text = "";
  for( var i=0; i < len; i++ ) {
    text += possible.charAt(getRandomInt(possible.length));
  }
  return text;
}

while (data.length < TOTAL_STRINGS) {
  data.push(makeRandomString(getRandomInt(20)));
}

Tests:

regex start
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var regex = window.regexStart; while (x < TOTAL_STRINGS) { const str = data[x]; regex.test(str); x += 1; }
startsWith
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; var match2 = window.match2; while (x < TOTAL_STRINGS) { const str = data[x]; str.startsWith(match) === 0; str.startsWith(match2) === 0; x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex start
startsWith

Fastest: N/A

Slowest: N/A

Latest run results:

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

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I'll break down the provided benchmark and explain what's being tested, compared, and their pros/cons.

**Benchmark Overview**

The test compares two approaches:

1. **Regex**: Using a regular expression (`regex`) to search for a pattern in strings.
2. **startsWith**: Using the `startsWith` method to check if a string starts with a specific value.

**Registry Functionality**

In the provided JSON, we have several registry functions defined at the top:

* `window.regexStart`: sets up a regular expression that matches "test" or "test2".
* `window.regexEnd`: sets up an end-of-string marker `/test$/`.
* `window.match` and `window.match2`: set up match values for "test" and "test2", respectively.
* `window.matchLength` stores the length of the match value.
* `window.data` stores an array of random strings generated by the `makeRandomString` function.

The registry functions are used to prepare the test environment, including setting up the regular expression and data arrays.

**Test Cases**

There are two individual test cases:

1. **Regex Start**: This test case uses the `regexStart` function to search for matches in each string in the `window.data` array.
2. **StartsWith**: This test case uses the `startsWith` method to check if each string starts with either `window.match` or `window.match2`.

**Comparison**

The comparison between the two approaches is performed by executing both tests and measuring their execution times.

**Pros/Cons of Each Approach**

* **Regex**: Pros:
	+ Can be used for complex pattern matching.
	+ Can be optimized using flags and other options.
* Cons:
	+ Can be slower due to parsing and compilation overhead.
	+ Can be less readable than other approaches.
* **startsWith**: Pros:
	+ Faster execution times, as it uses a built-in method.
	+ More readable, as it's a straightforward method call.
* Cons:
	+ Limited to checking if a string starts with a specific value.
	+ May not perform well on large datasets or complex patterns.

**Other Considerations**

* The `makeRandomString` function generates random strings for the test data. This can impact performance and readability of the benchmark.
* The use of `window.data` and `window.match`/`window.match2` as global variables may affect performance or security (if not properly sanitized).
* The comparison is done using a simple loop, which may not accurately represent real-world usage scenarios.

**Alternatives**

Other approaches to compare would include:

* Using other regular expression engines or libraries.
* Implementing custom string matching functions.
* Using other built-in methods, such as `includes` or `localeCompare`.
* Comparing performance with different optimization techniques (e.g., caching, memoization).

Keep in mind that this is just a general overview of the benchmark and may not cover all nuances. For deeper analysis, it's recommended to consult the MeasureThat.net documentation and explore the provided benchmark code in more detail.

Related benchmarks:

OR JS Regex vs 2 .startsWith (version: 0)

fork of https://www.measurethat.net/Benchmarks/Show/975/11/regex-vs-indexof-vs-startswith-vs-substr

Comparing performance of: regex start vs startsWith

Created: 4 years ago by: Guest

Jump to the latest result

regex start

startsWith

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):