Benchmark: Single vs multiple regex replace calls new new

Script Preparation code:

var str = "Et inventore ut est. Illum dolorem similique odit. Velit necessitatibus unde nostrum sequi ut pariatur suscipit sit magnam. Cum esse sed quod aut id. Recusandae vel commodi."

Tests:

Multiple, regex
str = str.replace(/a/g, 'A').replace(/e/g,'E')
Single, regex
str = str.replace(/a|e/g, match => match === 'a' ? 'A' : 'B')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Multiple, regex
Single, regex

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36

Browser/OS: Chrome 142 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Multiple, regex	10915417.0 Ops/sec
Single, regex	12534915.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the JSON evaluates the performance of two different approaches for replacing characters in a string using regular expressions in JavaScript. Specifically, it compares:

1. **Multiple `replace` Calls**: 
   - **Test Case**: `str = str.replace(/a/g, 'A').replace(/e/g,'E')`
   - **Description**: This approach uses chained calls to the `replace` method. For every occurrence of 'a', it is replaced with 'A', and for every occurrence of 'e', it is replaced with 'E'.
   - **Pros**:
     - Simplicity: Each replacement is straightforward and easy to implement.
     - Readability: Chained replacements can often be more intuitive to read.
   - **Cons**:
     - Performance: Multiple passes over the string engage the regex engine separately for each replacement, which can lead to slower performance, particularly on longer strings or with numerous substitutions.
   
2. **Single `replace` Call Using a Callback**:
   - **Test Case**: `str = str.replace(/a|e/g, match => match === 'a' ? 'A' : 'B')`
   - **Description**: This approach uses a single `replace` call with a regular expression that matches either 'a' or 'e'. A callback function determines what to replace the match with, returning 'A' for 'a' and 'B' for 'e'.
   - **Pros**:
     - Performance: Generally more efficient since it only traverses the string once, handling both replacements in one pass.
     - Flexibility: The callback allows for more complex logic for determining the replacement value, if needed.
   - **Cons**:
     - Complexity: Slightly more complex than the straightforward multiple replacements; developers need to understand how the callback works.
     - Readability: Might be less intuitive for someone unfamiliar with the callback pattern.

### Benchmark Results
The benchmark results highlighted the performance difference between the two approaches. The test using the single `replace` call achieved an execution speed of approximately **9.14 million** executions per second, while the multiple `replace` calls executed around **8.05 million** times per second. This indicates that the single callback method is significantly faster for this use case, confirming the performance benefits of minimizing passes over the string.

### Additional Considerations
1. **Use Case**: The chosen method might depend on specific application requirements. If simplicity and clarity are prioritized, a developer may opt for the multiple method. For performance-critical applications, it’s recommended to go with the single regex approach.
   
2. **Alternatives**: Other alternatives not specifically tested here could involve:
   - Using other libraries or regex engines that may offer optimized performance.
   - Manual string manipulation methods like using loops and condition checks, though this is generally less elegant and more error-prone compared to regex solutions.

In summary, the benchmark provides insight into the performance characteristics of two regex-based string replacement methods in JavaScript, allowing developers to make informed choices based on performance and code clarity.

Related benchmarks:

Single vs multiple regex replace calls new new (version: 1)

Comparing performance of: Multiple, regex vs Single, regex

Created: one year ago by: Guest

Jump to the latest result

Multiple, regex

Single, regex

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):