Benchmark: RegExp constructor vs literals, with variations

Script Preparation code:

function getReConstructor() {
  return new RegExp('^[0-9a-fA-F]{24}$').test('132abc67219f019afe12901a');
}
function getReFactory() {
  return RegExp('^[0-9a-fA-F]{24}$').test('132abc67219f019afe12901a');
}
function getReLiteral() {
  return /^[0-9a-fA-F]{24}$/.test('132abc67219f019afe12901a');
}
const premadeLiteral = /^[0-9a-fA-F]{24}$/;
function getRePremadeLiteral() {
  return premadeLiteral.test('132abc67219f019afe12901a');
}
const premadeConstructor = new RegExp('^[0-9a-fA-F]{24}$');
function getRePremadeConstructor() {
  return premadeConstructor.test('132abc67219f019afe12901a');
}
const premadeConstructor2 = new RegExp(/^[0-9a-fA-F]{24}$/);
function getRePremadeConstructor2() {
  return premadeConstructor2.test('132abc67219f019afe12901a');
}

Tests:

new RegExp()
getReConstructor()
RegExp() factory
getReFactory()
Literal
getReLiteral()
Literal premade
getRePremadeLiteral()
Premade constructor
getRePremadeConstructor()
Premade constructor 2
getRePremadeConstructor2()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new RegExp()
RegExp() factory
Literal
Literal premade
Premade constructor
Premade constructor 2

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser/OS: Chrome 103 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
new RegExp()	2716764.2 Ops/sec
RegExp() factory	2770801.2 Ops/sec
Literal	7673892.0 Ops/sec
Literal premade	7832211.5 Ops/sec
Premade constructor	7840322.5 Ops/sec
Premade constructor 2	7869570.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested, compared options, pros/cons of each approach, and other considerations.

**Benchmark Overview**

The benchmark measures the performance of creating regular expressions (regex) in JavaScript using different methods: literal strings, RegExp constructors, and pre-made literals. The goal is to compare the execution speed of these approaches.

**Test Cases**

There are six test cases:

1. `new RegExp()`: Creating a new RegExp object using the constructor.
2. `RegExp() factory`: Creating a new RegExp object using the factory function (not shown in the benchmark definition, but assumed to be similar to `getReFactory()`).
3. Literal: Using a literal string as a regex pattern.
4. Premade Literal: Using a pre-made literal string as a regex pattern.
5. Premade Constructor: Creating a new RegExp object using a pre-made RegExp constructor.
6. Premade Constructor 2: Similar to the previous test case, but with a slightly different RegExp constructor.

**Comparison of Approaches**

The main differences between these approaches are:

* **Literal strings**: These patterns are created as strings and then used as regex patterns. This approach is straightforward but might be slower due to string creation overhead.
* **RegExp constructors**: Creating new RegExp objects using the constructor is a common method in JavaScript. The benchmark tests how fast this approach is compared to literals.
* **Pre-made literals**: Pre-made literals are created beforehand and reused throughout the benchmark. This approach can reduce overhead by avoiding repeated string creation.

**Pros and Cons of Each Approach**

1. **Literal strings**:
	* Pros: Easy to understand, minimal overhead.
	* Cons: Can be slower due to string creation, less efficient for complex patterns.
2. **RegExp constructors**:
	* Pros: Fast, flexible, suitable for complex patterns.
	* Cons: Requires careful configuration and might be slower than pre-made literals.
3. **Pre-made literals**:
	* Pros: Reduces overhead by avoiding repeated string creation, easy to maintain.
	* Cons: Requires more setup, might not be as efficient for simple patterns.

**Other Considerations**

The benchmark also takes into account the device platform (Desktop), browser version (Chrome 103), and operating system (Mac OS X 10.15.7). These factors can affect performance due to differences in JavaScript engine optimizations, hardware capabilities, or browser-specific features.

**Library Usage**

None of the test cases explicitly use a JavaScript library. However, some libraries might be used implicitly through the use of built-in functions like `RegExp()` or `test()`, which are part of the JavaScript standard library.

**Special JS Features/Syntax**

There is no explicit mention of special JS features or syntax being used in this benchmark. The focus is on comparing different approaches to creating regular expressions.

Related benchmarks:

RegExp constructor vs literals, with variations (version: 0)

Testing performance when using a new RegExp object vs a literal regex

Comparing performance of: new RegExp() vs RegExp() factory vs Literal vs Literal premade vs Premade constructor vs Premade constructor 2

Created: 2 years ago by: Guest

Jump to the latest result

new RegExp()

RegExp() factory

Literal

Literal premade

Premade constructor

Premade constructor 2

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):