Benchmark: Regex vs String comparison

Tests:

Using string comparison
const contentType = 'application/json'; const match = contentType === 'application/json' || contentType === 'application/json; charset=utf-8'; console.log(match);
Using regex
const RE_CONTENT_TYPE_JSON = new RegExp('^application/json(; charset=utf-8)?$', 'i'); const contentType = 'application/json'; const match = RE_CONTENT_TYPE_JSON.test(contentType); console.log(match);
Using array includes
const contentType = 'application/json'; const match = ['application/json', 'application/json; charset=utf-8'].includes(contentType); console.log(match);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using string comparison
Using regex
Using array includes

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_1_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.1.1 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 18 on iOS 18.1.1

View result in a separate tab

Test name	Executions per second
Using string comparison	1147695.1 Ops/sec
Using regex	1019981.1 Ops/sec
Using array includes	1115549.6 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 benchmark and explore what's being tested, compared, and considered.

**Benchmark Overview**

The test compares three approaches to check if a string matches a certain pattern:

1. **String comparison**: Using the `===` operator to compare the string with two possible values.
2. **Regular expression (regex)**: Using a regex pattern to match the string against a set of possible values.
3. **Array includes**: Using the `includes()` method to check if the string is present in an array of possible values.

**Options Compared**

The benchmark compares these three approaches:

* **Pros and Cons:**
	+ String comparison:
		- Pros: Simple, easy to understand, and fast (no overhead from regex).
		- Cons: Limited flexibility, may not work with all edge cases.
	+ Regex:
		- Pros: Highly flexible, can match complex patterns, and works well with edge cases.
		- Cons: Slower due to the regex engine's overhead, more verbose configuration.
	+ Array includes:
		- Pros: Fast, easy to use, and reliable for simple use cases.
		- Cons: Limited flexibility, may not work with all edge cases (e.g., duplicate values).
* **Considerations:**
	+ Performance: Regex can be slower due to the engine's overhead, while array includes is generally fast. String comparison is likely the fastest but may require more manual handling for edge cases.
	+ Readability and Maintainability: Array includes might be easier to read and understand for simple use cases, while regex requires a deeper understanding of pattern syntax.

**Library Used**

None explicitly mentioned in the provided code. However, it's worth noting that the `RegExp` constructor is used in the regex approach.

**Special JS Features or Syntax**

There are no special features or syntax used in this benchmark.

**Benchmark Preparation Code and Definition**

The benchmark preparation code is empty (`"Script Preparation Code": null`), suggesting that the script is meant to be run directly without any setup. The `Html Preparation Code` is also empty, indicating that the benchmark doesn't require a specific HTML environment.

**Other Alternatives**

Other alternatives for string matching could include:

* Using a dedicated library like `fast-regex` or `regex-js`, which aim to improve performance and accuracy over the built-in `RegExp`.
* Implementing custom string matching algorithms, such as using a trie data structure.
* Utilizing other programming languages or frameworks that offer better performance or flexibility for string matching.

Keep in mind that these alternatives might not be directly comparable to the regex approach used here.

Related benchmarks:

Regex vs String comparison (version: 0)

Comparing performance of: Using string comparison vs Using regex vs Using array includes

Created: one year ago by: Registered User

Jump to the latest result

Using string comparison

Using regex

Using array includes

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):