Benchmark: Regex vs .indexOf vs .startsWith vs .indexof

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; }
.indexOf
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.indexOf(match) === 0; 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) === 0; x += 1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
.indexOf
includes()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36

Browser/OS: Chrome 107 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Regex	371.8 Ops/sec
.indexOf	7957.8 Ops/sec
includes()	8331.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared options, pros and cons, library usage, special JavaScript features or syntax, and other considerations.

**What is being tested:**

The benchmark tests three different ways to perform string matching:

1. **Regex**: Uses a regular expression to test if a given string matches a specific pattern.
2. **.indexOf()**: Tests if the index of the first occurrence of a substring in another string is equal to 0.
3. **includes()**: Tests if a string includes another string.

**Options compared:**

Each option has its own strengths and weaknesses:

* **Regex**: Pros:
	+ Highly flexible and powerful for matching patterns.
	+ Can be used for character classes, escaping, and grouping.
	+ Cons:
		- Can be slower than other options due to complexity.
		- Requires proper escape sequences and syntax.
* **.indexOf()**: Pros:
	+ Fast and efficient for exact matches.
	+ Easy to use and understand.
	+ Cons:
		- Only returns the index of the first occurrence, not the actual match.
		- Fails if the substring is not found.
* **includes()**: Pros:
	+ Fast and efficient for substring matching.
	+ Returns a boolean value indicating presence or absence.
	+ Cons:
		- Can be slower than .indexOf() due to method call overhead.
		- Not all browsers support includes() in older versions.

**Library usage:**

There is no external library used in this benchmark. The only custom script provided creates an array of random strings and assigns a regular expression, substring, and matching function to global variables for testing purposes.

**Special JavaScript features or syntax:**

None are explicitly mentioned or utilized in the provided benchmark. However, it's worth noting that the use of `window` object and global variables might be specific to MeasureThat.net's environment.

**Other considerations:**

* **Test data**: The test data consists of an array of random strings with varying lengths.
* **Performance**: Measuring performance is crucial in this context, as it provides insight into the efficiency of each matching method.
* **Browser and OS variations**: The benchmark results are reported for different browsers (Chrome 107) and operating systems (Mac OS X 10.15.7), which helps to identify potential platform-specific differences.

**Alternatives:**

Other alternatives to test string matching could include:

* Using a testing framework like Jest or Mocha with built-in string matching utilities.
* Implementing custom string matching functions using regular expressions, substring methods, or other techniques.
* Comparing the performance of different programming languages (e.g., JavaScript, Python, C++) when performing string matching.

Related benchmarks:

Regex vs .indexOf vs .startsWith vs .indexof (version: 0)

Testing some things

Comparing performance of: Regex vs .indexOf vs includes()

Created: 2 years ago by: Guest

Jump to the latest result

Regex

.indexOf

includes()

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):