Benchmark: Reuse Global Regex? RegEx.test vs. String.match vs. String.search

Script Preparation code:

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

Tests:

RegEx.test
/Hello/g.test(string);
String.match
string.match(regex);
String.search
string.search(regex)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
RegEx.test
String.match
String.search

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explore what's being tested.

**Benchmark Overview**

The benchmark compares three approaches for matching a regular expression (regex) against a string:

1. `RegEx.test()`
2. `String.match()`
3. `String.search()`

These methods are used to perform global pattern matching, which is useful in scenarios like validating input data or parsing text.

**Options Compared**

The benchmark tests the performance of each method on three different approaches:

* Using `RegEx.test()` with a global flag (`/Hello/g`)
* Using `String.match()` with a regular expression
* Using `String.search()` with a regular expression

These approaches differ in how they handle the regex pattern and the string being matched.

**Pros and Cons of Each Approach**

1. **`RegEx.test()` with global flag (`/Hello/g`)**
	* Pros:
		+ Efficient for global matching, as it only makes one pass through the entire string.
		+ Returns an array of matches if there are multiple occurrences of the pattern.
	* Cons:
		+ Can be slower than other methods for small strings or simple patterns due to its overhead.
2. **`String.match()` with a regular expression**
	* Pros:
		+ Fast and lightweight, making it suitable for large strings or complex patterns.
	* Cons:
		+ Only returns the first match, if any. Subsequent calls require rebuilding the regex pattern.
3. **`String.search()` with a regular expression**
	* Pros:
		+ Returns the index of the first match (or -1 if no match is found).
	* Cons:
		+ Can be slower than other methods due to its recursive search approach.

**Library and Purpose**

None of the libraries mentioned in the benchmark definition are specific, but we can infer that `RegEx` is a built-in JavaScript object for working with regular expressions. It provides various methods for matching patterns against strings, including `test()`, `match()`, and `search()`.

**Special JS Feature or Syntax (Not Applicable)**

There's no special feature or syntax mentioned in the benchmark definition that requires specific knowledge of JavaScript beyond basic understanding of regular expressions and string manipulation.

**Other Alternatives**

If you were to implement this benchmark yourself, here are some additional methods you might consider:

* Using `String.prototype.replace()` with a callback function for replacing patterns
* Utilizing a dedicated regex engine or library like RegEx4j (for Java)
* Employing a different matching approach, such as using a finite state machine

Keep in mind that the performance differences between these approaches can be significant, depending on the specific use case and requirements.

In conclusion, this benchmark provides valuable insights into the relative performance of various regex-based string matching methods in JavaScript. By understanding the strengths and weaknesses of each approach, you can make informed decisions about which method to use for your specific needs.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36

Browser/OS: Chrome 116 on Windows

View result in a separate tab

Test name	Executions per second
RegEx.test	5201936.0 Ops/sec
String.match	1548793.8 Ops/sec
String.search	3312010.5 Ops/sec

Related benchmarks:

Reuse Global Regex? RegEx.test vs. String.match vs. String.search (version: 0)

Comparing performance of: RegEx.test vs String.match vs String.search

Created: one year ago by: Guest

Jump to the latest result

RegEx.test

String.match

String.search

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):