Benchmark: Regex vs split/join correct

Script Preparation code:

var str = '/3123/213/123/412/41/4';

Tests:

Regex
str.replace(/\//g, "$&Z");
Split and Join
str.split('/').join('/Z');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
Split and Join

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 days ago):

LLMs can make mistakes. Check important info.

The benchmark titled "Regex vs split/join correct" compares two different string manipulation techniques in JavaScript for inserting a character (in this case, "Z") after every forward slash ("/") in a given string. The provided string for testing is `'/3123/213/123/412/41/4'`.

### Test Cases

1. **Regex**:
   - **Benchmark Definition**: `str.replace(/\\//g, "$&Z");`
   - **Description**: This approach uses a regular expression to match every occurrence of a forward slash (`/`) in the string. The `replace` function is utilized here with a global flag (`g`) to perform the operation on all matches. The `$&` syntax within the replacement string refers to the matched substring, which allows us to insert "Z" immediately after each match.
   - **Pros**:
     - Powerful for complex string manipulations.
     - Concise, especially when dealing with patterns.
   - **Cons**:
     - May have a slightly higher performance cost due to the overhead of regex processing, especially for simpler tasks.
     - Regex syntax can be less intuitive for developers unfamiliar with regular expressions.

2. **Split and Join**:
   - **Benchmark Definition**: `str.split('/').join('/Z');`
   - **Description**: This method first splits the string into an array at every occurrence of "/", resulting in an array of substrings. It then joins these substrings back together, inserting "/Z" between each segment.
   - **Pros**:
     - Simpler and more intuitive for developers who may not be comfortable with regex.
     - Often performs better for straightforward string concatenation tasks, as seen in the benchmark results.
   - **Cons**:
     - Less efficient for more complex pattern matching or manipulations, as it requires creating an intermediate array.

### Benchmark Results
The results from the benchmark demonstrate that the "Split and Join" method significantly outperforms the "Regex" approach in terms of executions per second:
- **Split and Join**: 4,351,575.5 executions per second.
- **Regex**: 1,341,738.125 executions per second.

### Considerations
- **Performance**: When it comes to performance, as evidenced by the benchmark results, the "Split and Join" method is much faster for this specific task, suggesting that for simple string manipulations, avoiding regex can lead to better performance.
- **Readability**: For maintainability and team collaboration, code clarity is essential. The "Split and Join" method may be preferred for developers who prioritize code readability over slight performance gains provided by regex in certain scenarios.
  
### Alternatives
Other than the techniques tested, there are several alternatives developers might consider:
- **String.prototype.replaceAll** (when supported in the environment): This method allows you to replace all occurrences of a substring without needing a regex, but it doesn't provide as much flexibility for pattern matching.
- **Templates and String Interpolation**: For certain tasks, using template literals or tagged template literals can be an alternative, especially when constructing new strings. However, they do not directly apply to this specific use case.
- **Native JavaScript Looping**: Manual iterations using a `for` loop or `forEach` with an `if` condition could also be employed, providing complete control over the logic but often at the expense of performance and succinctness.

In conclusion, the choice between regex and split/join approaches should consider the specific use case, developer familiarity, and performance implications. While regex offers significant power for pattern matching, simpler methods like split/join can often yield better performance and clarity for straightforward tasks, as shown in this benchmark.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser/OS: Firefox 132 on Windows

View result in a separate tab

Test name	Executions per second
Regex	1341738.1 Ops/sec
Split and Join	4351575.5 Ops/sec

Related benchmarks:

Regex vs split/join correct (version: 1)

Comparing performance of: Regex vs Split and Join

Created: 3 days ago by: Guest

Jump to the latest result

Regex

Split and Join

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 days ago):