Benchmark: manual replace vs regex replace

Script Preparation code:

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

Tests:

replace manual
"https://www.testurl.com" .replace('www.', '') .replace('http://', '') .replace('https://', '');
replace regex
"https://www.testurl.com".replace(new RegExp(/^(https?:\/\/)?(www\.)?/, 'g'), '');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
replace manual
replace regex

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:147.0) Gecko/20100101 Firefox/147.0

Browser/OS: Firefox 147 on Linux

View result in a separate tab

Test name	Executions per second
replace manual	11442681.0 Ops/sec
replace regex	8159211.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Description**

The provided benchmark compares two approaches to replace a specific string pattern in a URL: manual replacement using the `String.prototype.replaceAll` method and regular expression (regex) replacement using the `replace()` method with a regex pattern.

**Options Compared**

1. **Manual Replacement**: This approach uses the `String.prototype.replaceAll` method, which iterates over each character of the string and replaces it if it matches the specified search value.
2. **Regex Replacement**: This approach uses the `replace()` method with a regex pattern, which is more efficient than manual replacement for complex patterns.

**Pros and Cons**

* **Manual Replacement**:
	+ Pros: Easy to understand and implement, no additional libraries required.
	+ Cons: Can be slow for large strings due to the iteration over each character.
* **Regex Replacement**:
	+ Pros: Faster and more efficient than manual replacement, especially for complex patterns.
	+ Cons: Requires knowledge of regex syntax and can be harder to read.

**Library Usage**

The benchmark uses the `String.prototype.replaceAll` method, which is a built-in JavaScript method. No external libraries are required.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in this benchmark.

**Other Considerations**

When choosing between manual replacement and regex replacement, consider the following:

* If you need to perform simple string replacements with few occurrences, manual replacement might be sufficient.
* For complex patterns or large strings, regex replacement is likely a better choice.
* Be mindful of performance and readability when using regex patterns.

**Alternatives**

Other alternatives for replacing strings in JavaScript include:

1. **String.prototype.replace()**: A more modern alternative to `String.prototype.replaceAll`.
2. **Substitution functions**: You can write custom substitution functions that use a loop or recursion to replace strings.
3. **Third-party libraries**: There are many third-party libraries available, such as regex-optimizer or es-string-replace, that provide optimized string replacement algorithms.

In conclusion, the provided benchmark compares two approaches to replace a specific string pattern in a URL: manual replacement using `String.prototype.replaceAll` and regex replacement using the `replace()` method with a regex pattern. The choice between these approaches depends on the complexity of the pattern, performance requirements, and readability considerations.

Related benchmarks:

manual replace vs regex replace (version: 0)

Comparing performance of: replace manual vs replace regex

Created: 3 years ago by: Guest

Jump to the latest result

replace manual

replace regex

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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