Benchmark: replaceAll vs regex replace made in beethovben

Script Preparation code:

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

Tests:

replace regex
"this is it".replace(/ /g, "+");
replace All
"this is it".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

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down what is being tested in this benchmark.

**Overview**
The benchmark compares two approaches to replace substrings in a string: using the `String.prototype.replace()` method with a regular expression (regex) and using a custom function called `replaceAll()`. The test aims to determine which approach is faster and more efficient.

**Options compared**

1. **`replace()` with regex**: This option uses the built-in `replace()` method of the String prototype, but provides a custom search pattern using a regex. The regex is executed with the `g` flag (global) at the end, meaning it will replace all occurrences of the pattern in the string.
2. **`replaceAll()`**: This is the custom function defined in the benchmark's Script Preparation Code. It takes two arguments: the search pattern and the replacement string.

**Pros and cons**

1. `replace()` with regex:
	* Pros:
		+ Widely supported and well-optimized by browsers.
		+ Can handle more complex patterns, such as anagrams or Unicode characters.
	* Cons:
		+ May be slower due to overhead from the regex engine.
		+ Less control over the replacement process (e.g., no ability to specify a replacement string).
2. `replaceAll()`: This custom function provides more control over the replacement process but may have a performance penalty due to its custom implementation.

**Library used**
None is explicitly mentioned, as this benchmark focuses on the JavaScript engine's behavior rather than any external libraries.

**Special JS feature or syntax**
The test uses a feature called "arrow functions" (e.g., `String.prototype.replaceAll = function(search, replacement) { ... }`). This is not specific to the benchmark itself but is a common pattern in modern JavaScript. The test also uses template literals (`"\"this is it\".replace(/ /g, \"+\");"`), which are available in ECMAScript 2015 (ES6) and later versions.

**Other alternatives**

If you were to rewrite this benchmark using different approaches or libraries, some options could include:

1. Using a library like `regex-escape` to generate escaped patterns for the regex.
2. Implementing a custom replacement function using `Set` data structures.
3. Comparing the performance of using strings as regular expressions versus using `RegExp` constructors.

Keep in mind that these alternatives would change the fundamental nature of the benchmark, and you'd need to adjust the test cases and expected results accordingly.

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/88.0.4324.104 Safari/537.36

Browser/OS: Chrome 88 on Windows

View result in a separate tab

Test name	Executions per second
replace regex	6454224.0 Ops/sec
replace All	1577179.2 Ops/sec

Related benchmarks:

replaceAll vs regex replace made in beethovben (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 25 days ago):