Benchmark: Trimming leading/trailing string of characters

Script Preparation code:

var TestString = " ,".repeat(200) + '='.repeat(20000) + " ,".repeat(200);

var regexTrim = function(str, str2) {
    return str.replace(/^[ ,]+|[ ,]+$/g, '');
};

function indexTrim(str, ch) {
    var start = 0, 
        end = str.length;

    while(start < end && (str[start] === ch[0] || str[start] === ch[1]))
        ++start;

    while(end > start && (str[end - 1] === ch[0] || str[end - 1] === ch[1]))
        --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;
}

Tests:

Index Version (Jason Larke)
indexTrim(TestString, " ,");
Regex Version (leaf)
regexTrim(TestString, " ,")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Index Version (Jason Larke)
Regex Version (leaf)

Fastest: N/A

Slowest: N/A

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

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Let's break down the benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark definition represents a JavaScript function that trims leading and trailing characters from a string. There are four different implementations:

1. `indexTrim(str, ch)`: This function uses a simple iterative approach to find the first and last occurrences of the character in the string.
2. `regexTrim(str, str2)`: This function uses a regular expression to match and replace the leading and trailing characters from the string.
3. `booleanTrim(str, ch)`: This function uses the `split()` method with a regular expression to split the string into an array of substrings, filters out empty strings using `Boolean`, and then joins them back together using the same separator.
4. `spreadTrim(str, ch)`: This function uses the spread operator (`...`) to find the index of the character in the string, reverses the string, finds the last occurrence of the character, and then returns a substring from the original string starting at the first occurrence.

**Comparison**

The benchmark compares the performance of these four implementations on the same test case:

* `TestString`: A long string containing leading and trailing characters (`" ,".repeat(200) + '='.repeat(20000) + " ,".repeat(200)`).
* The character to trim: `" ,"`.

**Pros and Cons**

Here's a brief summary of each implementation's pros and cons:

1. `indexTrim(str, ch)`: This approach is simple and efficient but may not be suitable for larger strings or more complex trimming scenarios.
	* Pros: Simple, fast
	* Cons: May not work for larger strings or multiple characters to trim
2. `regexTrim(str, str2)`: This approach uses a regular expression to match and replace the leading and trailing characters from the string.
	* Pros: Works with any character sequence, relatively efficient
	* Cons: Requires regular expressions, may be slower than native implementation
3. `booleanTrim(str, ch)`: This approach uses the `split()` method to split the string into substrings, filters out empty strings, and then joins them back together.
	* Pros: Works with any character sequence, relatively efficient
	* Cons: May create temporary arrays and objects, slower than native implementation
4. `spreadTrim(str, ch)`: This approach uses the spread operator to find the index of the character in the string, reverses the string, finds the last occurrence of the character, and then returns a substring.
	* Pros: Works with any character sequence, relatively efficient
	* Cons: Requires modern JavaScript features (spread operator), may be slower than native implementation

**Library and Special JS Features**

The benchmark uses the `split()` method, which is a built-in JavaScript method. The `repeat()` method, `indexOf()`, and `substring()` methods are also used.

The benchmark does not use any external libraries or special JavaScript features beyond what's required for the implementations themselves.

**Other Alternatives**

If you want to optimize string trimming in JavaScript, you may consider using:

* `String.prototype.trim()`: A built-in method that removes leading and trailing whitespace characters.
* `String.prototype.replace()` with a regular expression: Can be used to remove specific characters from the start and end of a string.
* `Array.prototype.slice()`: Can be used to extract a substring from an array or string.

Keep in mind that the performance of these alternatives may vary depending on the specific use case and browser.

Related benchmarks:

Trimming leading/trailing string of characters (version: 0)

Comparing performance of: Index Version (Jason Larke) vs Regex Version (leaf)

Created: 3 years ago by: Guest

Jump to the latest result

Index Version (Jason Larke)

Regex Version (leaf)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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