Benchmark: replaceAll vs regex replace . with ,

Script Preparation code:

String.prototype.replaceAll = function(search, replacement) {
    var target = this;
    return target.replace(new RegExp(search, 'g'), replacement);
};

Tests:

replace regex
"78.24".replace(/./g, ",");
replace All
"78.24".replaceAll(",", ".");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
replace regex
replace All

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.1 Safari/605.1.15

Browser/OS: Safari 18 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
replace regex	645398912.0 Ops/sec
replace All	17468190.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark definition and test cases measure the performance of two different approaches for replacing characters in a string: using regular expressions (`/./g, \`,`) and a custom `replaceAll` method (String.prototype.replaceAll).

**Test Cases**

There are two test cases:

1. **"replace regex"`**: This test case uses a regular expression to replace each character in the input string `"78.24"` with a comma. The regular expression `/./g` matches any single character (`.`) globally (`g`) across all characters in the string.
2. **"replace All"`**: This test case uses the custom `replaceAll` method (String.prototype.replaceAll) to replace each character in the input string `"78.24"` with a dot (`\`). The `replaceAll` method takes three arguments: the search value, the replacement value, and the context value.

**Library**

The `replaceAll` method is a part of the JavaScript standard library, introduced in ECMAScript 2015 (ES6). Its purpose is to provide a concise way to replace multiple occurrences of a pattern in a string with another string. In this benchmark, it's used as a custom implementation for replacement.

**Regular Expressions**

The regular expression `/./g` used in the "replace regex" test case matches any single character (`.`) across all characters in the input string. The `g` flag at the end makes the match global, meaning that once a match is found, the search starts from the next character.

**Performance Comparison**

The benchmark compares the performance of two approaches:

1. **Regular Expressions**: Using regular expressions to replace each character with a comma.
2. **Custom Replacing (replaceAll)**: Using the `replaceAll` method to replace each character with a dot (`\`).

Pros and Cons:

* Regular Expressions:
	+ Pros: Provides a flexible way to match patterns across all characters in a string.
	+ Cons: Can be slower than custom implementations due to the overhead of regular expression parsing and matching.
* Custom Replacing (replaceAll):
	+ Pros: Typically faster than regular expressions, as it avoids the overhead of parsing and matching a pattern.
	+ Cons: May not provide the same flexibility as regular expressions for more complex replacements.

**Other Alternatives**

If you wanted to implement this benchmark yourself, you could use other approaches, such as:

* Using `String.prototype.replace()` with a callback function
* Using `Array.prototype.map()` and `String.fromCharCode()`
* Implementing your own simple replacement algorithm using loops

However, keep in mind that these alternatives might not provide the same performance characteristics as the custom `replaceAll` method or regular expressions.

I hope this explanation helps you understand what's being tested in the provided benchmark!

Related benchmarks:

replaceAll vs regex replace . with , (version: 0)

Comparing performance of: replace regex vs replace All

Created: 3 years ago by: Guest

Jump to the latest result

replace regex

replace All

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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