Benchmark: replace vs custom replace

Script Preparation code:

function doReplace(str) {
    if (str != null && str.length > 0 && str.charAt(str.length - 5) == '/test') {
        str = str.substring(0, str.length - 5);
    }
    return str;
}

Tests:

DoReplace
var res = doReplace('https://goog/test');
Replace
var res1 = 'https://goog/test'.replace('/test');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
DoReplace
Replace

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 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 two approaches to replace a specific string pattern in a given input string:

1. **Custom Replace**: The script preparation code defines a function `doReplace(str)` that checks if the last 5 characters of the input string are '/test'. If so, it removes those characters from the end of the string using the `substring()` method.
2. **Built-in String Replace**: The script preparation code is empty, but the benchmark definition uses the built-in string replacement operator `/test` to replace the pattern.

**Comparison Options**

The two approaches being compared are:

1. **Custom Replace**: Uses a custom JavaScript function to implement the replacement logic.
	* Pros: Can be more flexible and customizable, as it allows for arbitrary implementation of the replacement logic.
	* Cons: May have performance overhead due to the additional function call and potential type checking.
2. **Built-in String Replace**: Uses the built-in string replacement operator `/test` to replace the pattern.
	* Pros: Faster execution, as it leverages the optimized implementation provided by the JavaScript engine.
	* Cons: Less flexible, as it only supports a limited set of patterns.

**Other Considerations**

Both approaches assume that the input string is a UTF-16 encoded string. If the input string uses a different encoding, additional considerations may be necessary.

The benchmark also assumes that the last 5 characters of the input string are exactly '/test', without any escape sequences or other modifications. If this assumption does not hold true for all test cases, the results may be affected.

**Library**

There is no explicit library mentioned in the benchmark definition or script preparation code.

**Special JS Feature/Syntax**

The built-in string replacement operator `/test` is used in the benchmark definition. This feature is part of the JavaScript language specification and allows for regular expression-based string matching.

**Other Alternatives**

If you were to rewrite this benchmark using a different approach, some alternatives could be:

1. Using a dedicated library like `String.prototype.replace()` or `RegExp` to perform the replacement.
2. Implementing the replacement logic using a loop or iteration instead of the built-in operator.
3. Using a different encoding scheme for the input string.

For example, if you wanted to use the `String.prototype.replace()` method, your script preparation code would look like this:
```javascript
function doReplace(str) {
  return str.replace('/test', '');
}
```
Keep in mind that these alternatives may affect the performance and results of the benchmark.

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/88.0.4324.192 Safari/537.36

Browser/OS: Chrome 88 on Windows

View result in a separate tab

Test name	Executions per second
DoReplace	8100884.5 Ops/sec
Replace	5030237.5 Ops/sec

Related benchmarks:

replace vs custom replace (version: 0)

replace vs custom replace

Comparing performance of: DoReplace vs Replace

Created: 3 years ago by: Guest

Jump to the latest result

DoReplace

Replace

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):