Benchmark: Case Insensitive RegEx.test vs. String.includes

Script Preparation code:

var string = "Hello world!";
var regex = /hello/i;

Tests:

RegEx.test
regex.test(string);
String.includes
string.toLowerCase().includes("hello");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
RegEx.test
String.includes

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
RegEx.test	7441614.0 Ops/sec
String.includes	16207477.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided benchmark.

**Benchmark Overview**

The benchmark compares two approaches for case-insensitive string matching: using the `test()` method of a regular expression object (`regex.test`) and using the `includes()` method with `toLowerCase()` transformation on the string.

**What are we testing?**

We're comparing the execution performance of these two approaches:

1. `regex.test(string);`: This method tests if the entire string matches the regular expression pattern, ignoring case. The regex object is created beforehand (`var regex = /hello/i;`).
2. `string.toLowerCase().includes("hello");`: This approach converts the input string to lowercase using `toLowerCase()` and then uses the `includes()` method to search for the substring "hello" in the converted string.

**Options Compared**

The two options being compared are:

1. **Regex.test**: Using a regular expression object's built-in `test()` method.
2. **String.includes with T.toLowerCase()**: Converting the input string to lowercase and using the `includes()` method.

**Pros and Cons of Each Approach:**

1. **Regex.test**:
	* Pros:
		+ Efficient for simple pattern matching (i.e., "hello" in a short regex).
		+ Often faster than other approaches due to compiler optimizations.
	* Cons:
		+ Can be slower for complex patterns or large strings.
		+ Requires creating a regex object beforehand, which may incur overhead.
2. **String.includes with T.toLowerCase()**:
	* Pros:
		+ Simple and easy to implement.
		+ Fast for short substrings in larger strings (due to optimized `includes()` implementation).
	* Cons:
		+ Requires additional string processing (converting to lowercase) and potential cache misses.

**Library and Purpose:**

In this benchmark, the regex library is used implicitly by JavaScript's built-in regular expression engine. The purpose of using a regex object (`regex`) is to define a pattern that can be matched against input strings.

**Special JS Feature or Syntax:**

There are no specific JavaScript features or syntaxes being tested in this benchmark, other than those inherent to the `test()` and `includes()` methods themselves.

**Other Alternatives:**

If not using regex, some alternative approaches for case-insensitive string matching could include:

1. Using a different string search algorithm, like `indexOf()` with a similar approach.
2. Implementing a custom string comparison function that converts inputs to lowercase or uses a case-insensitive flag.
3. Utilizing a third-party library or module providing optimized string matching functions.

However, for most use cases, the built-in `test()` and `includes()` methods are likely sufficient and efficient enough, making alternative approaches less necessary.

Keep in mind that benchmarking results may vary depending on specific JavaScript engines, browser versions, and system configurations.

Related benchmarks:

Case Insensitive RegEx.test vs. String.includes (version: 0)

Comparing performance of: RegEx.test vs String.includes

Created: 10 months ago by: Guest

Jump to the latest result

RegEx.test

String.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):