Benchmark: String.prototype.replaceAll vs regular expression

Script Preparation code:

var dynamicParam = 'someParam';

Tests:

Regular expression
'test [[someParam]] string'.replace(new RegExp(`\\[\\[${dynamicParam}]]`, 'g'), 'replaced');
String.prototype.replaceAll
'test [[someParam]] string'.replaceAll(`[[${dynamicParam}]]`, 'replaced')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regular expression
String.prototype.replaceAll

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, the options compared, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark is defined in JSON format, which provides details about the test case:

* `Name`: The name of the benchmark, which is "String.prototype.replaceAll vs regular expression".
* `Description`: An empty description, suggesting that this benchmark may be used to compare performance between two methods.
* `Script Preparation Code` and `Html Preparation Code`: These fields are left blank, indicating that no additional setup or configuration is required for the test.

**Individual Test Cases**

Two test cases are defined:

1. **Regular expression**: This test case uses a JavaScript RegExp object to replace occurrences of a dynamic parameter (`dynamicParam`) in a string.
	* The `Benchmark Definition` line uses the `replace()` method, passing a regular expression as an argument. The regular expression matches any occurrence of the escaped double-bracket (`\\\\[\\\\[${dynamicParam}]`).
2. **String.prototype.replaceAll**: This test case uses the `replaceAll()` method on the `String.prototype`, which is a part of the JavaScript standard library.
	* The `Benchmark Definition` line uses the same string replacement pattern as in the regular expression example, but wrapped in double-brackets (`[[${dynamicParam}]]`) to match the expected input format.

**Library and Purpose**

Both test cases use a part of the JavaScript standard library:

* `RegExp`: A built-in object that provides support for regular expressions.
* `String.prototype`: An extension of the String object, providing additional methods and properties.

**Special JS Feature or Syntax**

The `replaceAll()` method is an ES6 feature (introduced in 2015) that allows using a non-RegExp replacement function. This syntax is used to simplify string replacements, especially when dealing with simple patterns like this one.

**Pros and Cons of Each Approach**

Both approaches have their trade-offs:

* **Regular Expression**: Pros:
	+ More flexible than `replaceAll()`, allowing for more complex patterns.
	+ Less magic (no ES6 feature), potentially more compatible across browsers and environments.
* **String.prototype.replaceAll**: Pros:
	+ Easier to read and understand, with a more explicit syntax.
	+ Less prone to errors due to the simplified pattern matching.

Cons:

* `RegExp`:
	+ More verbose and error-prone for simple cases like this one.
	+ May perform better for complex patterns or large strings.
* `String.prototype.replaceAll`: Pros:
	+ Smoother, more user-friendly syntax.
	+ May be faster due to the optimized implementation in JavaScript engines.

**Other Considerations**

When choosing between these approaches, consider the trade-off between flexibility and ease of use. If you need a simple, straightforward replacement with a familiar pattern (e.g., double-bracket notation), `String.prototype.replaceAll` might be the better choice. For more complex patterns or a high degree of customization, using a regular expression may be necessary.

**Alternatives**

Other alternatives for string replacements include:

* Using a dedicated library like jQuery's `grep()` or `filter()` methods.
* Implementing custom replacement logic using functions and loops.
* Leveraging other features like `String.prototype.replace()` with a callback function (although this is less efficient than `replaceAll()`).

Keep in mind that these alternatives might introduce additional overhead, complexity, or compatibility issues.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Browser/OS: Chrome 113 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Regular expression	1942052.5 Ops/sec
String.prototype.replaceAll	4317516.5 Ops/sec

Related benchmarks:

String.prototype.replaceAll vs regular expression (version: 0)

Comparing performance of: Regular expression vs String.prototype.replaceAll

Created: 2 years ago by: Guest

Jump to the latest result

Regular expression

String.prototype.replaceAll

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):