Benchmark: RegEx.exec vs regex.test

Script Preparation code:

var string = "Hello world!";
var regex = /[A-Z][a-z]+ [a-z]+/;

Tests:

regex.exec
regex.exec(string);
regex.test
regex.test(string);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex.exec
regex.test

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 days ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 147 on Android

View result in a separate tab

Test name	Executions per second
regex.exec	40922256.0 Ops/sec
regex.test	58867800.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its results.

**What is being tested?**

The benchmark measures the performance difference between two approaches when using regular expressions (regex) in JavaScript: `exec` vs `test`. Specifically, it tests how many times each method can execute a regex pattern on a given string.

**Options compared**

There are two options being compared:

1. **Regex.exec**: This method attempts to match the entire regex pattern against the input string and returns an array of matches or null if no match is found.
2. **regex.test**: This method only checks whether the regex pattern can be applied to the string without actually executing it.

**Pros and cons**

* **Regex.exec**: Pros:
	+ Can return actual matches, which might be useful in certain situations.
	+ Might be faster for some use cases because it executes the regex pattern directly.
Cons:
	+ May throw an error if no match is found or if the input string is invalid.
	+ Returns more data than necessary (the entire array of matches).
* **regex.test**: Pros:
	+ Faster and more lightweight because it only checks compatibility without executing the regex pattern.
	+ Less memory usage since it doesn't return any data.
Cons:
	+ Only returns a boolean value indicating whether the regex pattern can be applied to the string.
	+ Might not be suitable for use cases that require actual matches.

**Library and purpose**

The `regex.test` method uses the `String.prototype.test()` method, which is a built-in JavaScript method. This method is part of the ECMAScript standard and is widely supported across different browsers and environments.

**Special JS feature or syntax**

None mentioned in this benchmark. However, it's worth noting that `exec` and `test` methods have some differences in terms of their behavior when used with non-standard regex patterns or edge cases.

**Other alternatives**

If you need more control over the regex pattern execution or want to optimize performance for specific use cases, you might consider using other approaches:

1. **String.prototype.replace()**: While not directly comparable to `exec` and `test`, `replace()` can be used to perform a similar operation with more flexibility.
2. **Regular expression engines like Sizzle or MicroParse**: These engines provide optimized regex pattern execution and parsing for performance-critical applications.

In summary, the benchmark compares two popular methods for working with regular expressions in JavaScript: `exec` vs `test`. The results indicate that `regex.test` is faster and more lightweight but less suitable for use cases requiring actual matches.

Related benchmarks:

RegEx.exec vs regex.test (version: 0)

Comparing performance of: regex.exec vs regex.test

Created: 4 years ago by: Guest

Jump to the latest result

regex.exec

regex.test

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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