Benchmark: Regex vs split/join - nb fork

Script Preparation code:

var string = 'testCase';

Tests:

Regex
string.split(/(?=[A-Z])/).join(' ');
Split and Join
let finalString = ""; for (let i = 0; i < string.length; i++) { if (string[i].toUpperCase() === string[i]) { finalString += ` ${string[i]}`; } else { finalString += string[i]; } }

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

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
Regex	993553.9 Ops/sec
Split and Join	99321.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark is designed to compare two approaches for processing strings in JavaScript:

1. **Regular Expressions (Regex)**: Using `string.split(/(?=[A-Z])/).join(' ')`
2. **Split and Join**: A custom loop-based approach, which concatenates characters to a final string based on certain conditions.

**What's being tested**

The benchmark measures the performance of these two approaches, specifically:

* The time it takes to execute each benchmark definition
* The number of executions per second (ExecutionsPerSecond) for each browser and device platform

**Options Compared**

We have two options being compared:

1. **Regex**: Using regular expressions to split and join strings.
	* Pros:
		+ Can be more concise and expressive than custom loops.
		+ Often faster due to optimized JavaScript engine implementations.
	* Cons:
		+ Can be slower for very large strings or complex patterns.
		+ May have additional overhead due to pattern matching and compilation.
2. **Split and Join**: A custom loop-based approach.
	* Pros:
		+ More control over the processing pipeline.
		+ Might be faster for specific use cases (e.g., very large strings).
	* Cons:
		+ Often less concise and more prone to errors than regex.
		+ May have slower performance due to the overhead of loop iterations.

**Library Used**

There is no explicit library mentioned in the benchmark definition. However, it's possible that some JavaScript engines or browsers might be using optimized implementations of regular expressions under the hood.

**Special JS Feature/Syntax**

The benchmark uses the `(?=[A-Z])` pattern in the regex, which is a positive lookahead assertion. This feature is part of the modern ECMAScript standard (ECMAScript 2015+) and allows for more flexible and efficient string manipulation.

Other alternatives to consider:

* **String.prototype.replace()**: Another approach could be using the `replace()` method with a callback function to achieve similar results.
* **Array.prototype.map()**: Mapping over an array of characters might provide a similar performance profile as the custom loop-based approach.
* **Libraries like Lodash or Ramda**: These libraries often provide optimized string manipulation functions that could be used for this benchmark.

Keep in mind that these alternatives are not explicitly mentioned in the provided benchmark definition, and their performance profiles might vary depending on the specific use case.

Related benchmarks:

Regex vs split/join - nb fork (version: 0)

Comparing performance of: Regex vs Split and Join

Created: 3 years 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 llama3.2:3b, generated one month ago):