Benchmark: RegExp constructor vs literal using exec

Script Preparation code:

var reConstructor = new RegExp('^[0-9a-fA-F]{24}$')
var reLiteral = /^[0-9a-fA-F]{24}$/

Tests:

new RegExp()
reConstructor.exec('132abc67219f019afe12901a')
Literal
reLiteral.exec('132abc67219f019afe12901a')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new RegExp()
Literal

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 Edg/141.0.0.0

Browser/OS: Chrome 141 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
new RegExp()	16826312.0 Ops/sec
Literal	16741214.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark compares the performance of two approaches:

1. **RegExp constructor**: Creating a new RegExp object using the `new` keyword.
2. **Literal regex with exec method**: Using a literal regex string and calling the `exec()` method on it.

**Options Compared**

The benchmark is comparing the execution speed of these two approaches when searching for a specific pattern in a given string.

**Pros and Cons of Each Approach**

1. **RegExp constructor**:
	* Pros: Can be more flexible, as you can create complex regex patterns using the `pattern` and `flags` properties.
	* Cons: May lead to slower performance due to the overhead of creating a new RegExp object.
2. **Literal regex with exec method**:
	* Pros: Can be faster for simple cases, as it avoids the overhead of creating a new RegExp object.
	* Cons: Limited flexibility, as you're stuck with a fixed pattern.

**Other Considerations**

* The benchmark uses the `exec()` method, which can stop at the first match, potentially affecting performance.
* The strings used in the test are 24 characters long, which is likely the maximum length of an Ethereum address (used for testing).

**Library Used**

None explicitly mentioned. However, RegExp objects use the ECMAScript Standard library.

**Special JS Feature or Syntax**

No special features or syntax are being tested in this benchmark.

**Alternative Approaches**

For similar benchmarks:

* Using a regex engine like libregex or regex-js
* Comparing other string searching methods, such as `indexOf()` or `includes()`
* Testing performance with different regex flags (e.g., `g`, `i`, `m`)

Keep in mind that benchmarking can be highly dependent on the specific test case and JavaScript environment. The results may vary depending on the execution context.

Related benchmarks:

RegExp constructor vs literal using exec (version: 0)

Testing performance when using a new RegExp object vs a literal regex with exec method

Comparing performance of: new RegExp() vs Literal

Created: 3 years ago by: Guest

Jump to the latest result

new RegExp()

Literal

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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