Benchmark: RegEx.test vs. String.includes vs. String.match vs String.match(regex) for starting string

Script Preparation code:

var string = "Hello world!";
var regex = /^Hello/g;

Tests:

RegEx.test
regex.test(string);
String.includes
string.startsWith("Hello");
String.match
string.match("Hello");
String.match with regex
string.match(regex);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
RegEx.test
String.includes
String.match
String.match with regex

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
RegEx.test	30144346.0 Ops/sec
String.includes	55967220.0 Ops/sec
String.match	4604230.0 Ops/sec
String.match with regex	9796805.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark.

**Benchmark Definition**

The website `MeasureThat.net` allows users to create and run JavaScript microbenchmarks. The provided benchmark definition involves comparing four different approaches for checking if a string starts with a specified substring:

1. `String.includes` (with `string.startsWith`)
2. `String.match`
3. `String.match(regex)` where `regex` is a regular expression defined as `/^Hello/g`

**Options Compared**

The options being compared are the performance of each approach in terms of number of executions per second.

**Pros and Cons of Different Approaches:**

1. **String.includes (with `string.startsWith`):**
	* Pros:
		+ Widely supported by most browsers.
		+ Easy to implement, as it's a built-in method.
	* Cons:
		+ May be slower than other approaches due to the overhead of checking if a string includes a substring.
2. **String.match:**
	* Pros:
		+ More flexible than `includes` or `test`, as it returns an array of matches instead of just the first match.
	* Cons:
		+ May return false positives (empty matches) if the regex is not properly defined.
3. **String.match(regex):**
	* Pros:
		+ Can be more efficient than `includes` or `match` when dealing with complex patterns, as it compiles the regex beforehand.
	* Cons:
		+ Requires a properly defined regex, which can be error-prone.
4. **Regular Expresses (regex) in general:**
	* Pros:
		+ Can match complex patterns and perform advanced string operations.
	* Cons:
		+ May have performance overhead due to compilation and execution of the regex.

**Library/Functionality Used**

The benchmark uses `String.match` and a custom-defined regular expression `/^Hello/g`. The library used is part of the JavaScript standard library, as `String.match` is a built-in method.

**Special JS Feature/Syntax**

The benchmark uses the `/g` flag at the end of the regex, which enables global matching. This allows the regex to match all occurrences of the pattern in the string instead of just the first one.

**Other Alternatives**

If you need to perform string matching or regular expressions in JavaScript, other alternatives include:

1. `String.prototype.replace()`: Can be used for replacing patterns, but may not be as efficient as `match` or regex.
2. `Array.prototype.find()` and friends: Can be used for finding the first occurrence of a pattern, but may not be suitable for all use cases.
3. Third-party libraries like RegEx.js or String-Parse: Can provide more advanced regular expression capabilities, but may introduce additional dependencies.

In summary, the benchmark is comparing the performance of four different approaches for checking if a string starts with a specified substring, highlighting the trade-offs between simplicity, flexibility, and performance.

Related benchmarks:

RegEx.test vs. String.includes vs. String.match vs String.match(regex) for starting string (version: 0)

Comparing performance of: RegEx.test vs String.includes vs String.match vs String.match with regex

Created: 2 years ago by: Guest

Jump to the latest result

RegEx.test

String.includes

String.match

String.match with regex

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):