Benchmark: regex v. slice - MeasureThat.net

Script Preparation code:

test = '\n  test\n'

Tests:

sli
test.slice( test.charCodeAt(0) == 10, test.length - ( test.charCodeAt(test.length - 1) == 10) )
reg
test.replace(/^\n|\n$/g, '')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
sli
reg

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
sli	2874757.0 Ops/sec
reg	7487183.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark defines two test cases:

1. `regex v. slice` (defined in the script preparation code)
2. `sli` and `reg` (individual test cases)

The first one, `regex v. slice`, compares the performance of regular expressions (`test.replace`) with string slicing (`test.slice`). The benchmark script sets up a test string with a newline character (`\n`) at the beginning and end.

**Script Preparation Code**

The script preparation code is:
```javascript
test = '\n  test\n';
```
This creates a test string with a single newline character at the beginning and end.

**Individual Test Cases**

There are two individual test cases:

1. `sli`: This test case uses the slicing method (`test.slice`) to extract a substring from the test string.
2. `reg`: This test case uses regular expressions (`test.replace(/^\\n|\\n$/g, '')`) to remove newline characters from the beginning and end of the test string.

**Library Used**

None mentioned in the benchmark definition. However, it's likely that Chrome is using its built-in V8 JavaScript engine, which has an optimized regex implementation.

**Special JS Feature/Syntax**

There are two special features used:

1. **Slicing**: The `slice()` method is used to extract a substring from the test string.
2. **Regular Expressions**: The `replace()` method with a regular expression (`/^\s|\s$/g`) is used to remove whitespace characters (newline, space) from the beginning and end of the test string.

**Pros and Cons**

Here are some pros and cons for each approach:

1. **Slicing:**
	* Pros:
		+ Fast and efficient
		+ Simple and easy to use
	* Cons:
		+ May not handle edge cases correctly (e.g., multiple consecutive newline characters)
2. **Regular Expressions:**
	* Pros:
		+ Flexible and powerful
		+ Can handle complex patterns and edge cases
	* Cons:
		+ Slower than slicing for simple use cases
		+ More complex to set up and optimize

**Other Alternatives**

If you want to compare other methods, here are some alternatives:

1. **Using `String.prototype.trim()`**: This method removes whitespace characters from the beginning and end of a string.
2. **Using `String.prototype.replace()` with a different regex pattern**: You could try using a different regex pattern to remove newline characters (e.g., `/\\n/g` or `\r\n+/g`).
3. **Using `indexOf()` and `substring()` methods**: These methods allow you to search for a specific character or substring and extract a portion of the string.

Keep in mind that each method has its own strengths and weaknesses, and the choice ultimately depends on your specific use case and performance requirements.

Related benchmarks:

regex v. slice (version: 0)

Comparing performance of: sli vs reg

Created: one year ago by: Guest

Jump to the latest result

sli

reg

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):