Benchmark: Split join vs replace

Script Preparation code:

var example = 'AgreementChangeId'

Tests:

split + join
var result = example.split(/(?=[A-Z])/).join(' ');
replace
var result = example.replace(/([A-Z]+)/g, ' $1')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
split + join
replace

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
split + join	5094835.0 Ops/sec
replace	6946143.5 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):

LLMs can make mistakes. Check important info.

This benchmark tests two different approaches to modifying a string: splitting and joining versus using the `replace` method.

**Here's a breakdown:**

* **Test Case 1: "split + join"**:
    * This approach uses the `.split()` method with a regular expression `/(?=[A-Z])`/ to split the string at every uppercase letter. The resulting array is then joined back together using spaces (`join(' ')`).  
* **Test Case 2: "replace"**:
    * This approach uses the `.replace()` method with the regular expression `(/([A-Z]+)/g)` to replace each sequence of uppercase letters with a space followed by the matched group.

**Pros and Cons:**

* **`split + join`**:
    * **Pro:** Can be more flexible if you need to perform additional operations on the split parts before joining them back together. 
    * **Con:**  Can potentially be slower, as it involves creating an array and then iterating over it. 
* **`replace`**:
    * **Pro:** Often more concise and can be faster in some cases because it directly modifies the original string without creating intermediate arrays.
    * **Con:** Less flexible if you need to perform complex manipulations on the parts of the string before replacing them.

**Library Usage:** This benchmark does not utilize any external JavaScript libraries.

**Special JS Features/Syntax**: The code uses a regular expression with a positive lookahead assertion `(?=[A-Z])` to match the position of an uppercase letter without including it in the match.

**Alternatives**:
* **String Interpolation:**  In newer JavaScript versions, template literals (````) provide a cleaner and more readable way to format strings, which might be suitable for this task if you need to dynamically insert values into the string.

Let me know if you have any further questions or want to explore any of these aspects in more detail!

Related benchmarks:

Split join vs replace (version: 0)

Comparing performance of: split + join vs replace

Created: 3 years ago by: Guest

Jump to the latest result

split + join

replace

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):