Benchmark: RegEx.exec vs String.match

Script Preparation code:

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

Tests:

regex.exec
regex.exec(string);
string.match
string.match(regex);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex.exec
string.match

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 15 hours ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:137.0) Gecko/20100101 Firefox/137.0

Browser/OS: Firefox 137 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
regex.exec	40213480.0 Ops/sec
string.match	31348750.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is being tested?**

The provided benchmark compares two approaches to execute regular expressions (RegEx) in JavaScript:

1. `regex.exec(string)`
2. `string.match(regex)`

These two methods are used to search for a pattern within a string and return an array of matches, or null if no match is found.

**Options compared:**

There are two options being compared:

1. **RegexExec**: Using the `exec()` method to execute the regular expression.
2. **StringMatch**: Using the `match()` method to search for a pattern in a string.

**Pros and Cons of each approach:**

**RegexExec (using exec())**

Pros:

* Can return more information about the match, such as the index and offset of the match.
* Can be used with more advanced regular expression features like groups and named capture groups.

Cons:

* Can be slower than `match()` for simple patterns, since it needs to execute the entire pattern from scratch.
* Can use more memory, especially if the pattern is complex or uses many capture groups.

**StringMatch (using match())**

Pros:

* Generally faster than `exec()`, since it can reuse cached results for similar patterns.
* Requires less memory, as it only needs to store the pattern and not execute the entire string from scratch.

Cons:

* Returns null if no match is found, whereas `exec()` returns an object with the match or null.
* May not support some advanced regular expression features like groups and named capture groups.

**Library usage**

In this benchmark, no external libraries are used. However, it's worth noting that both `exec()` and `match()` methods can be influenced by the JavaScript engine's optimization algorithms, which might introduce performance variations depending on the specific engine implementation.

**Special JS feature or syntax**

There is no special JavaScript feature or syntax mentioned in this benchmark. The focus is solely on comparing two basic approaches to executing regular expressions.

**Other alternatives**

If you're looking for alternative methods to execute regular expressions, consider the following:

* **RegExp.prototype.test()**: A more lightweight method that returns a boolean indicating whether the pattern matches at least one position in the string.
* **String.prototype.replace()**: Can be used with a regex pattern and a replacement function to perform a global replace operation on a string.

Keep in mind that these alternatives may have different performance characteristics compared to `exec()` and `match()`, so it's essential to test them separately if needed.

Related benchmarks:

RegEx.exec vs String.match (version: 0)

Comparing performance of: regex.exec vs string.match

Created: 4 years ago by: Guest

Jump to the latest result

regex.exec

string.match

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):