Benchmark: regex vs double replace

Script Preparation code:

var testStr = '[marketCode::US]';
var outputStr = '';

Tests:

regex
outputStr = testStr.replace(/[\[\]]/g, '');
double replace
outputStr = testStr.replace('[', '').replace(']', '');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex
double replace

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 9 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two approaches to remove special characters from a string: using regular expressions (regex) and double replacing.

**Script Preparation Code**

The script preparation code is as follows:
```javascript
var testStr = '[marketCode::US]';
var outputStr = '';
```
This sets up the input string `testStr` with a specific value containing special characters, and initializes an empty string `outputStr`.

**Html Preparation Code**

There is no HTML preparation code provided.

**Test Cases**

The benchmark consists of two test cases:

1. **Regex**: The benchmark definition for this test case is:
```javascript
outputStr = testStr.replace(/[\\[\\]]/g, '');
```
This uses the `replace()` method with a regular expression to remove all occurrences of `\[]` (which represents an escape sequence) from the input string.

2. **Double Replace**: The benchmark definition for this test case is:
```javascript
outputStr = testStr.replace('[', '').replace(']', '');
```
This uses two separate `replace()` methods to remove both '[' and ']' characters from the input string.

**Library Used**

In the "regex" test case, no specific library is used. However, it's worth noting that the `replace()` method is a built-in JavaScript function.

**Pros and Cons of Each Approach**

1. **Regex**: Using regex can be more efficient and flexible when dealing with complex pattern matching. However:
	* It may be slower due to the overhead of parsing and compiling the regular expression.
	* The use of special characters (`\[]`) may require additional escaping or handling.
2. **Double Replace**: This approach is simple and straightforward but:
	* May be less efficient for large input strings, as it involves two separate replacements.
	* Can be error-prone if not implemented correctly.

**Other Considerations**

When choosing between these approaches, consider the following:

* Complexity of the pattern: If you need to match complex patterns, regex might be a better choice. For simple cases like this one, double replace might suffice.
* Input string size: For large input strings, regex might be more efficient due to its ability to handle multiple replacements in a single pass.
* Performance: If speed is critical, consider using a microbenchmarking framework that can provide detailed performance statistics.

**Alternative Approaches**

Other alternatives for removing special characters from a string include:

1. Using `substring()` or `slice()` methods with string slicing.
2. Employing a simple loop to manually remove characters.
3. Utilizing a custom function with logic-specific to your use case.

Keep in mind that these alternative approaches might not be as efficient or flexible as regex or double replace, depending on the specific requirements of your project.

Overall, this benchmark provides a simple and straightforward way to compare the performance of two common string manipulation techniques in JavaScript.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36

Browser/OS: Chrome 96 on Windows

View result in a separate tab

Test name	Executions per second
regex	3404877.0 Ops/sec
double replace	2730128.0 Ops/sec

Related benchmarks:

regex vs double replace (version: 0)

Comparing performance of: regex vs double replace

Created: 2 years ago by: Guest

Jump to the latest result

regex

double replace

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 9 days ago):