Benchmark: Asterisk map replace vs stored regex replace vs make an array replace

Script Preparation code:

var re = /./gi;
function mapReplace(value) {
  return value.split("").map((x, index, arr) => "*").join("")
}

function makeArrayReplace(value) {
  return (new Array(value.length)).fill("*").join("");
}

function regexReplace(value) {
  return value.replace(re, "*");
}

Tests:

Map replace
const input = "abcdefghijklmnopqrstuvwxyz"; mapReplace(input);
Regex replace
const input = "abcdefghijklmnopqrstuvwxyz"; regexReplace(input);
Make array replace
const input = "abcdefghijklmnopqrstuvwxyz"; makeArrayReplace(input);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map replace
Regex replace
Make array replace

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark definition is a JSON object that describes the test scenario:
```json
{
  "Name": "Asterisk map replace vs stored regex replace vs make an array replace",
  "Description": null,
  "Script Preparation Code": "...",
  "Html Preparation Code": null
}
```
The script preparation code provides three different functions:

1. `mapReplace(value)`: This function replaces each character in the input string with a star (`*`) by using the `split()` method to split the string into an array, mapping over the array to replace each element with a star, and then joining the array back into a string.
2. `makeArrayReplace(value)`: This function creates a new array with the same length as the input string, fills it with stars (`*`), and then joins the array back into a string.
3. `regexReplace(value)`: This function uses a regular expression to replace each character in the input string with a star (`*`) using the `replace()` method.

**Individual Test Cases**

The benchmark definition includes three individual test cases:

1. "Map replace"
2. "Regex replace"
3. "Make array replace"

Each test case has its own executable code snippet:
```javascript
const input = "abcdefghijklmnopqrstuvwxyz";
mapReplace(input);
```

```javascript
const input = "abcdefghijklmnopqrstuvwxyz";
regexReplace(input);
```

```javascript
const input = "abcdefghijklmnopqrstuvwxyz";
makeArrayReplace(input);
```
These test cases are designed to execute each of the three functions and measure their performance.

**Pros and Cons**

Here's a brief analysis of the pros and cons of each approach:

1. `mapReplace(value)`: This function is using array manipulation, which can be slower than other approaches.
	* Pros: Easy to understand and implement.
	* Cons: May incur overhead due to array creation and manipulation.
2. `makeArrayReplace(value)`: This function creates a new array with the same length as the input string, fills it with stars (`*`), and then joins the array back into a string.
	* Pros: Can be faster than other approaches since it avoids creating multiple temporary strings.
	* Cons: Requires more memory to store the intermediate array.
3. `regexReplace(value)`: This function uses regular expressions to replace each character in the input string with a star (`*`).
	* Pros: Can be fast and efficient since regular expressions are optimized for performance.
	* Cons: May incur overhead due to regex compilation and execution.

**Library Usage**

None of the test cases use any external libraries. However, the `regexReplace(value)` function relies on built-in JavaScript regular expression support.

**Special JS Features or Syntax**

There's no special JavaScript feature or syntax being used in this benchmark beyond the standard language features mentioned earlier (e.g., array manipulation, string concatenation).

**Other Alternatives**

If you were to reimplement this benchmark using alternative approaches, some options might include:

1. Using a different data structure, such as a string buffer or a char array, instead of strings.
2. Employing a different replacement strategy, such as replacing with a specific Unicode character instead of a star (`*`).
3. Implementing the `mapReplace(value)` function using a language construct like `reduce()` or `forEach()`.
4. Using a just-in-time (JIT) compiler to optimize the performance of one of the functions.

Keep in mind that rewriting the benchmark with new approaches might require significant changes to the code and may not necessarily provide better results. The existing implementation is likely optimized for the specific use case and hardware architecture.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:72.0) Gecko/20100101 Firefox/72.0

Browser/OS: Firefox 72 on Windows

View result in a separate tab

Test name	Executions per second
Map replace	1247872.2 Ops/sec
Regex replace	1164045.8 Ops/sec
Make array replace	1995265.0 Ops/sec

Related benchmarks:

Asterisk map replace vs stored regex replace vs make an array replace (version: 0)

Comparing performance of: Map replace vs Regex replace vs Make array replace

Created: 4 years ago by: Guest

Jump to the latest result

Map replace

Regex replace

Make array replace

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):