Benchmark: forEach vs regex in vowel counting

Tests:

forEach version
// useful for HtmlCollection, NodeList, String types function forEach(array, callback, scope){for (var i=0,n=array.length; i<n; i++)callback.call(scope, array[i], i, array);} // passes back stuff we need function countVowels(input) { var vowels = 'aeiou', result = 0; forEach( input, function(char){ if (vowels.indexOf(char) != -1) result++; } ); return result; } countVowels("goes");
regexVersion
function VowelCount(str) { var pattern = /[aeiou]/i; var vowelCount = 0; for (var i = 0; i < str.length; i++) { if (pattern.test(str[i])){ vowelCount++; } } return vowelCount; } VowelCount("goes")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach version
regexVersion

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided benchmark compares two approaches to count the number of vowels in a given string: using the `forEach` method and using a regular expression (`regex`). We'll break down what each approach does, its pros and cons, and discuss other considerations.

**1. Using `forEach`:**

```javascript
function forEach(array, callback, scope) {
    for (var i = 0, n = array.length; i < n; i++) {
        callback.call(scope, array[i], i, array);
    }
}

function countVowels(input) {
    var vowels = 'aeiou', result = 0;
    forEach(input, function(char) {
        if (vowels.indexOf(char) != -1) result++;
    });
    return result;
}
```

The `forEach` method is a built-in JavaScript function that applies a given callback function to each element of an array. In this case, the callback function checks if the character is a vowel and increments the result accordingly.

**Pros:**

* Easy to read and understand.
* Works with any iterable (array, string, etc.).

**Cons:**

* May have performance overhead due to the callback function invocation.
* Can be slower for very large strings or arrays.

**2. Using regular expression (`regex`):**

```javascript
function VowelCount(str) {
    var pattern = /[aeiou]/i;
    var vowelCount = 0;

for (var i = 0; i < str.length; i++) {
        if (pattern.test(str[i])) {
            vowelCount++;
        }
    }

return vowelCount;
}
```

The regular expression `[aeiou]` matches any character that is a vowel (both lowercase and uppercase). The `i` flag at the end makes the match case-insensitive. In this implementation, we use the `test()` method to check if each character is a vowel.

**Pros:**

* Fast and efficient for matching patterns.
* Can be more concise than using `forEach`.

**Cons:**

* May not work as expected with very large strings or arrays due to memory constraints.
* Less readable for some developers (due to the use of regex).

**Library usage:**

In this benchmark, the `forEach` method is a built-in JavaScript function. No external library is used.

**Special JS feature:**

None mentioned in this specific benchmark. However, it's worth noting that JavaScript has several features that can affect performance, such as:

* `let` and `const` declarations (vs. traditional `var`)
* Arrow functions
* Spread operators
* Object destructuring

These features can impact the performance of certain code snippets, but their effects are often subtle and depend on the specific use case.

**Alternatives:**

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

1. **Lodash**: A popular JavaScript utility library that provides various functions for tasks like array manipulation.
2. **Radium**: Another JavaScript library that offers performance-oriented string matching and searching algorithms.
3. **V8**: The open-source JavaScript engine used in Google Chrome, which can be used as a reference implementation for benchmarking JavaScript performance.

Keep in mind that the choice of alternative approach depends on your specific use case and requirements.

I hope this explanation helps!

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:129.0) Gecko/20100101 Firefox/129.0

Browser/OS: Firefox 129 on Linux

View result in a separate tab

Test name	Executions per second
forEach version	14167874.0 Ops/sec
regexVersion	18621818.0 Ops/sec

Related benchmarks:

forEach vs regex in vowel counting (version: 0)

Comparing performance of: forEach version vs regexVersion

Created: 8 years ago by: Guest

Jump to the latest result

forEach version

regexVersion

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):