Benchmark: Trimming leading/trailing characters (multiple)

Script Preparation code:

var TestString = '+'.repeat(200) + '='.repeat(20000) + '+'.repeat(200);

var regexTrim = function(str, ch) {
    if (ch === ']') ch = '\\]';
    else if (ch === '^') ch = '\\^';
    else if (ch === '\\') ch = '\\\\';
    return str.replace(new RegExp('^[' + ch + ']+|[' + ch + ']+$', 'g'), '');
};

function indexTrim(str, ch) {
    var start = 0, 
        end = str.length;

    while(start < end && str[start] === ch)
        ++start;

    while(end > start && str[end - 1] === ch)
        --end;

    return (start > 0 || end < str.length) ? str.substring(start, end) : str;
}

function booleanTrim(str, ch) {
    return str.split(ch).filter(Boolean).join(ch);
}

function spreadTrim(str, ch) {
    const first = [...str].findIndex(char => char !== ch);
    const last = [...str].reverse().findIndex(char => char !== ch);
    return str.substring(first, str.length - last);
}

function substringTrim(str, ch) {
    while(str.charAt(0)==ch) {
        str = str.substring(1);
    }

    while(str.charAt(str.length-1)==ch) {
        str = str.substring(0,str.length-1);
    }

    return str;
}

function trimSuffix(str, suffix) {
    let lastStrChar = str.length - 1, lastSuffixChar = suffix.length - 1;
    while (lastSuffixChar >= 0) {
        if (str[lastStrChar] !== suffix[lastSuffixChar]) return str;
        lastStrChar--;
        lastSuffixChar--;
    }
    return str.slice(0, lastStrChar + 1)
}

Tests:

Index Version (Jason Larke)
indexTrim(TestString, '+');
Regex Version (leaf)
regexTrim(TestString, '+')
Boolean Filter Version (mbaer3000)
booleanTrim(TestString, '+')
Spread Version (Robin F.)
spreadTrim(TestString, '+')
Substring Version (Pho3niX83)
substringTrim(TestString, '+')
Index Multiple Char Version (Pawel O.)
trimSuffix(TestString, '+')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Index Version (Jason Larke)
Regex Version (leaf)
Boolean Filter Version (mbaer3000)
Spread Version (Robin F.)
Substring Version (Pho3niX83)
Index Multiple Char Version (Pawel O.)

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Index Version (Jason Larke)	1343272.6 Ops/sec
Regex Version (leaf)	161773.9 Ops/sec
Boolean Filter Version (mbaer3000)	187392.5 Ops/sec
Spread Version (Robin F.)	8524.0 Ops/sec
Substring Version (Pho3niX83)	425688.6 Ops/sec
Index Multiple Char Version (Pawel O.)	103549560.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark in question evaluates various approaches to trim leading and trailing characters from a string in JavaScript. The string used for testing, `TestString`, consists of repeated '+' and '=' characters, making it particularly suited for examining how each method handles these leading and trailing characters.

### Options Compared

1. **Index Version (`indexTrim`)**:
   - This approach uses a simple loop to determine the starting and ending indices of the characters to trim. It iterates through the string until it finds characters that are not the specified target character to trim.
   - **Pros**: Straightforward implementation, very clear logic, and potentially efficient in simple cases where the target character is consistently at the start or end.
   - **Cons**: It may be less efficient for longer strings or strings with many characters to assess, as it performs a linear scan from both ends.

2. **Regex Version (`regexTrim`)**:
   - Utilizes regular expressions to define a pattern that matches the target character at both ends of the string.
   - **Pros**: Concise and powerful, capable of easily adapting to multiple target characters.
   - **Cons**: May have performance overhead due to regex engine processing, particularly if the input is large or complex.

3. **Boolean Filter Version (`booleanTrim`)**:
   - This method splits the string into an array by the target character, filters out the empty strings, and joins them back together.
   - **Pros**: It can effectively handle multiple contiguous characters and provide clean removal.
   - **Cons**: The overhead associated with array manipulation and the split operation may lead to reduced performance for larger strings.

4. **Spread Version (`spreadTrim`)**:
   - This implementation uses the spread operator to convert the string into an array and finds indices of characters that are not the target.
   - **Pros**: More modern syntax and potentially easier to understand for those familiar with ES6 features.
   - **Cons**: The spread operator can introduce overhead when dealing with very large strings due to creation of intermediate arrays.

5. **Substring Version (`substringTrim`)**:
   - This approach utilizes substring operations to trim characters directly from the string without additional data structures.
   - **Pros**: Directly manipulates the string and may have lower overhead compared to building arrays.
   - **Cons**: For long strings with extensive leading/trailing characters, it may still involve multiple operations.

6. **Trim Suffix Version (`trimSuffix`)**:
   - Specifically designed to trim a specified suffix from the string, iterating backward through the string character by character.
   - **Pros**: Highly efficient for cases where the suffix is known, especially when targeting a specific pattern.
   - **Cons**: Limited to trimming from the end and not flexible for leading characters unless modifying the implementation.

### Performance Insights

From the benchmark results, the predominant winner was the **Index Trim Version**, achieving over 103 million executions per second, indicating a very efficient implementation for the specific input type. The **Regex Version**, alongside **Substring** and **Boolean Filter Versions**, performed significantly slower, highlighting the efficacy of more straightforward index-based approaches for this type of problem input.

### Other Considerations

- **String Length**: The string used for benchmarking is essential; performance characteristics might vary drastically with differing lengths and compositions of strings.
- **Browser Variability**: Test results can change depending on the JavaScript engine (e.g., V8 in Chrome, SpiderMonkey in Firefox), so optimizations might behave differently across platforms.
- **Use Cases**: Depending on the broader context (like user inputs in web applications), the complexity and performance of each method might influence choices in practice.

### Alternatives

Beyond the discussed methods, additional strategies could include:
- **Built-in Methods**: Utilizing modern built-in methods such as `String.prototype.trim` (not effective for specific characters but useful for whitespace).
- **Libraries**: For more standardized string manipulations, libraries like Lodash or Underscore might offer wrappers or utility functions that are optimized and maintainable.
- **Maintenance Considerations**: Choosing a more verbose but clear method might sometimes outweigh the performance gains, especially if code maintainability and readability are priorities in the project.

In summary, the benchmark provides a perspective on different implementations for trimming operations in strings, weighing their performance, complexities, and suitable use cases.

Related benchmarks:

Trimming leading/trailing characters (multiple) (version: 1)

Comparing performance of: Index Version (Jason Larke) vs Regex Version (leaf) vs Boolean Filter Version (mbaer3000) vs Spread Version (Robin F.) vs Substring Version (Pho3niX83) vs Index Multiple Char Version (Pawel O.)

Created: one month ago by: Guest

Jump to the latest result

Index Version (Jason Larke)

Regex Version (leaf)

Boolean Filter Version (mbaer3000)

Spread Version (Robin F.)

Substring Version (Pho3niX83)

Index Multiple Char Version (Pawel O.)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):