Benchmark: replace speed - MeasureThat.net

Tests:

map
str = "102.7 KIIS FM" str = str .split(' ') .map(function(value){ if(value.toLowerCase() == "fm" || value.toLowerCase() == "am") return value return value.replace( /(\b.)|(.)/g, ($0, $1, $2) => { return ($1 && $1.toUpperCase()) || $2.toLowerCase(); } ); }) .join(' ');
regular
str = "102.7 KIIS FM" str = str .split(' ') .join(' ') .replace( /(\b.)|(.)/g, ($0, $1, $2) => { return ($1 && $1.toUpperCase()) || $2.toLowerCase(); } );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
regular

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition**

The provided JSON represents a benchmark definition for two test cases: `map` and `regular`. The benchmark is designed to measure the speed of replacing specific patterns in a string using regular expressions. However, instead of directly comparing the performance of different regex engines or libraries, MeasureThat.net compares the performance of applying the replacement function directly within the JavaScript engine (i.e., using the `replace()` method) versus applying it in two separate steps: splitting the string into an array, mapping over the array with a custom function, and then joining the array back together.

**Options Compared**

The benchmark is designed to compare the performance of:

1. **Direct Replacement**: Using the `replace()` method to replace the patterns directly in the string.
2. **Map and Join**: Splitting the string into an array, mapping over the array with a custom function, and then joining the array back together.

**Pros and Cons**

### Direct Replacement

Pros:

* Simple and straightforward approach
* No additional memory allocation or copying of data between arrays

Cons:

* May involve more overhead due to the `replace()` method's internal implementation (e.g., creating temporary arrays)

### Map and Join

Pros:

* Allows for more flexibility in applying custom transformations to each element
* Can be beneficial for complex string processing tasks

Cons:

* Involves additional memory allocation and copying of data between arrays, which can lead to performance penalties.

**Library Usage**

There is no explicit library mentioned in the benchmark definition. However, it's worth noting that some JavaScript engines, like V8 (used by Chrome), have built-in support for regular expressions and string manipulation functions. In this case, MeasureThat.net likely uses the V8 engine or a similar implementation of JavaScript.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax mentioned in the benchmark definition. The code uses standard JavaScript features like arrays, map functions, and regex patterns.

**Alternatives**

If you're interested in exploring alternative approaches to string replacement, here are a few options:

1. **Regex engines**: Implementing a custom regex engine, like PCRE (Perl-Compatible Regular Expressions), can provide more fine-grained control over the replacement process.
2. **String manipulation libraries**: Libraries like jQuery's `string` utility or specialized string processing libraries like `lodash.string` offer various string manipulation functions that might be comparable to the `map()` and `join()` approach used in this benchmark.
3. **Native string operations**: Depending on the specific use case, using native string operations like substring replacement or concatenation might be more efficient than applying regular expressions.

Keep in mind that these alternatives may not directly compare to the `map()` and `join()` approach used in this benchmark. The MeasureThat.net team likely chose this approach for its simplicity and relevance to common JavaScript use cases.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36

Browser/OS: Chrome 79 on Mac OS X 10.14.5

View result in a separate tab

Test name	Executions per second
map	192317.7 Ops/sec
regular	164436.0 Ops/sec

Related benchmarks:

replace speed (version: 0)

Comparing performance of: map vs regular

Created: 4 years ago by: Guest

Jump to the latest result

map

regular

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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