Benchmark: Regex vs startsWith

Tests:

Regex
const testString = 'QualtricsEOS|SV_7amJ2Dww8cWdtQh | FS_2zd0QZhebl4cRHT'; testString.match(/^QualtricsEOS\|(SV_[0-9a-zA-Z]{11,15})\|(FS_[0-9a-zA-Z]{11,15})$/);
startsWith
const testString = 'QualtricsEOS|SV_7amJ2Dww8cWdtQh | FS_2zd0QZhebl4cRHT'; testString.startsWith('QualtricsEOS');

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

startsWith

56.5M/s

Regex

12.2M/s

Fastest: startsWith (4.6x faster)

View exact numbers

✓ startsWith: 56,495,588 ops/sec
• Regex: 12,184,791 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
startsWith

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/149.0.0.0 Safari/537.36

Browser/OS: Chrome 149 on Mac OS X 10.15.7

View result in a separate tab

startsWith

57.1M/s

Regex

10.7M/s

View exact numbers

Test name	Executions per second
✓ startsWith	57,093,600 Ops/sec
Regex	10,656,233 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 JSON and understand what's being tested.

**Benchmark Definition**
The `Name` field is `Regex vs startsWith`, indicating that this benchmark compares the performance of regular expressions (`Regex`) with the `startsWith` method.

**Options Compared**

There are two options being compared:

1. **Regular Expressions (Regex)**
	* Pros:
		+ Can be used to match complex patterns, including character classes, quantifiers, and anchors.
		+ Can be used for validation and parsing.
	* Cons:
		+ Can be slower than other methods due to the overhead of compiling and executing regular expressions.
2. **startsWith Method**
	* Pros:
		+ Generally faster than regular expressions since it's a built-in method that can be optimized by the browser engine.
		+ Simplified syntax, making it easier to read and maintain.

**Other Considerations**

When deciding between regular expressions and the `startsWith` method, consider the following:

* If you need to perform complex pattern matching or validation, regular expressions might be a better choice. However, if you only need to check if a string starts with a specific substring, the `startsWith` method is likely faster and more efficient.
* Regular expressions can be sensitive to character encoding and Unicode normalization issues. In contrast, the `startsWith` method is generally more robust in these areas.

**Library and Special JS Feature**
In this benchmark, there doesn't appear to be any external library being used, nor are any special JavaScript features or syntax (like async/await, ES6 modules, etc.) being utilized.

**Alternatives**

If you wanted to test other approaches for string matching, some alternatives could include:

* **String.includes()**: Similar to `startsWith`, but searches for a substring anywhere in the string, not just at the beginning.
* **Substring Matching with String.indexOf() or String.lastIndexOf()**: These methods search for a specific character sequence within a string and return its index. However, they might be slower than regular expressions due to their more complex implementation.
* **Regular expression alternatives**: Some browsers may have additional, faster regular expression engines built-in (e.g., V8 in Chrome).

For this particular benchmark, the main choice between `Regex` and `startsWith` is a trade-off between performance and complexity. The `startsWith` method is likely to be faster for simple string matching tasks, while regular expressions provide more flexibility for complex pattern matching.

Regex vs startsWith (version: 0)

Comparing performance of: `Regex vs startsWith`

Created: 4 years ago by: Guest

Go to the latest result

Regex

startsWith

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Regex vs startsWith (version: 0)

Comparing performance of: Regex vs startsWith

Created: 4 years ago by: Guest

Go to the latest result

Regex

startsWith

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `Regex vs startsWith`