Benchmark: Regex vs .indexOf vs .startsWith vs .substr kasdfladjkf

HTML Preparation code:

<div></div>

Script Preparation code:

window.regex = /^test/;
window.match = 'test';
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
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; }
.includes
var x = 0; var TOTAL_STRINGS = window.TOTAL_STRINGS; var data = window.data; var match = window.match; while (x < TOTAL_STRINGS) { const str = data[x]; str.includes(match); x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
.includes

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

**Overview**

The provided benchmark, hosted on MeasureThat.net, aims to compare the performance of different string searching methods in JavaScript: regular expressions (`regex`), the `.indexOf()` method, and the `.startsWith()` method.

**Benchmark Definitions**

There are two main benchmark definitions:

1. **Regex**: This test case uses a regular expression to search for the pattern `test` within an array of randomly generated strings. The script prepares the data by generating 100,000 random strings and storing them in the `window.data` property.
2. **.includes**: This test case uses the `.includes()` method to check if a given string is present in an array of random strings.

**Options Compared**

The benchmark compares the following options:

* **Regex**: The built-in JavaScript regular expression engine
* **.indexOf()**: A method that returns the index of the first occurrence of a substring within a string
* **.startsWith()**: A method that returns `true` if the string starts with a given prefix

**Pros and Cons**

Here's a brief analysis of each approach:

* **Regex**:
	+ Pros: Highly flexible, can match complex patterns, and is widely supported.
	+ Cons: Can be slow for large strings or datasets due to its complexity and overhead.
* **.indexOf()**:
	+ Pros: Fast and efficient for small to medium-sized strings, as it only needs to scan the string once.
	+ Cons: May not be suitable for larger datasets or complex patterns.
* **.startsWith()**:
	+ Pros: Similar to `.indexOf()`, but optimized for checking if a string starts with a specific prefix.
	+ Cons: May not be as flexible as `regex` or as efficient as `.indexOf()` for large strings.

**Libraries and Special Features**

In this benchmark, there is no explicit mention of any third-party libraries or special features. However, it's worth noting that the JavaScript engine used by MeasureThat.net may have its own optimizations or quirks that could affect the results.

**Other Alternatives**

If you're interested in exploring alternative string searching methods, here are a few options:

* **Spline**: A library that provides a faster and more efficient way to search for patterns in strings.
* **StringSearch**: A lightweight library that offers a simple and fast way to perform substring searches.
* **Boyerkas Algorithm**: A heuristic algorithm that can be used to find the first occurrence of a substring in a string.

Keep in mind that these alternatives may not be as widely supported or well-maintained as the built-in JavaScript methods.

Related benchmarks:

Regex vs .indexOf vs .startsWith vs .substr kasdfladjkf (version: 0)

Testing some things

Comparing performance of: Regex vs .includes

Created: 3 years ago by: Guest

Jump to the latest result

Regex

.includes

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):