Benchmark: Replace tests - MeasureThat.net

Script Preparation code:

function replace(_input, _find, _replace) {
    var start = -1;
    var cursor = 0;
    var inputLength = _input.length;
    var findLength = _find.length;
    var newString = '';
    var buildString = '';
    if (_find.length === 1 && _replace.length === 1) {
        _input = _input.split('');
        while(_input[_input.indexOf(_find)] >= 0) {
            _input[_input.indexOf(_find)] = _replace;
        }
        newString = _input.join('');
    } else {
        for (var i = 0; i < inputLength; i++) {
            if (_input[i] === _find[cursor]) {
                if (start === -1) {
                    start = i;
                }
                if (findLength - 1 === i - start) {
                    newString += _replace;
                    buildString = '';
                    cursor = 0;
                    start = -1;
                } else {
                    buildString += _find[cursor];
                    cursor++;
                }
            } else {
                newString += buildString + _input[i];
                buildString = '';
                cursor = 0;
                start = -1;
            }
        }
    }
    return newString;
}
function replace2(_input, _find, _replace) {
    var start = -1;
    var cursor = 0;
    var inputLength = _input.length;
    var findLength = _find.length;
    var newString = '';
    var buildString = '';
    if (_find.length === 1 && _replace.length === 1) {
        newString = _input.split(_find).join(_replace);
    } else {
        for (var i = 0; i < inputLength; i++) {
            if (_input[i] === _find[cursor]) {
                if (start === -1) {
                    start = i;
                }
                if (findLength - 1 === i - start) {
                    newString += _replace;
                    buildString = '';
                    cursor = 0;
                    start = -1;
                } else {
                    buildString += _find[cursor];
                    cursor++;
                }
            } else {
                newString += buildString + _input[i];
                buildString = '';
                cursor = 0;
                start = -1;
            }
        }
    }
    return newString;
}

Tests:

Replace #1
replace('helle', 'el', 'a');
Replace #2
replace2('helle', 'el', 'a');
Replace #3
'helle'.replace('el', 'a');
Replace #4
'helle'.replace(/el/g, 'a');
Replace #5
'helle'.split('el').join('a');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Replace #1
Replace #2
Replace #3
Replace #4
Replace #5

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested, compared options, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark definition consists of two JavaScript functions: `replace` and `replace2`. Both functions are designed to replace a specific substring (`_find`) with another string (`_replace`) in a given input string (`_input`). The differences between the two functions lie in their implementation:

1.  **Replace Function**
    *   `replace` function uses a traditional loop-based approach.
    *   It checks if the length of `_find` is equal to 1 and `_replace` is also 1, which means it's only replacing a single character at a time.
    *   If not, it iterates over each character in the input string. When it encounters a match with `_find`, it replaces the matched character with `_replace`. Otherwise, it simply concatenates the remaining characters to the result.
2.  **Replace Function #2**
    *   `replace2` function uses the more efficient and widely supported approach of using the `String.prototype.split()` and `String.prototype.join()` methods or a regular expression (`/el/g`).
    *   When `_find` is a single character, it uses `split()` to split the input string at each occurrence of `_find`, replacing the matched substring with `_replace`.

**Test Cases**

The benchmark includes five test cases:

1.  `replace('helle', 'el', 'a');`
2.  `replace2('helle', 'el', 'a');`
3.  `'helle'.replace('el', 'a');` (string method call)
4.  `'helle'.replace(/el/g, 'a');` (regular expression with global flag)
5.  `'helle'.split('el').join('a');` ( splitting and joining)

**Comparison Options**

1.  **Traditional Loop-Based Approach (`replace`)**
    *   Simple to implement
    *   May be slower than other approaches due to the explicit loop
2.  **Regular Expression with Global Flag (`/el/g`)**
    *   More efficient for matching multiple occurrences
    *   Can be less readable due to the use of regular expressions
3.  **Split and Join Methods (`replace2` with `split()` and `join()`)
    *   Fastest approach, but only works if `_find` is a single character or can be split
    *   More complex implementation

**Pros and Cons**

1.  **Traditional Loop-Based Approach (`replace`)**
    *   Pros: Simple to implement, predictable performance
    *   Cons: May be slower than other approaches due to the explicit loop
2.  **Regular Expression with Global Flag (`/el/g`)**  
    *   Pros: More efficient for matching multiple occurrences, can handle edge cases
    *   Cons: Can be less readable due to the use of regular expressions, may not work well with large inputs
3.  **Split and Join Methods (`replace2` with `split()` and `join()`)**
    *   Pros: Fastest approach, simple implementation for single character replacements
    *   Cons: May not work well if `_find` is not a single character or cannot be split

**Other Considerations**

*   The benchmark includes multiple browsers (Chrome 57) to account for varying performance characteristics.
*   The `DevicePlatform` and `OperatingSystem` fields provide additional context about the testing environment.

In conclusion, this benchmark compares three approaches for replacing a substring in an input string: a traditional loop-based approach (`replace`), a regular expression with global flag (`/el/g`), and the more efficient split and join methods (`replace2` with `split()` and `join()`). The choice of approach depends on the specific requirements, such as performance, readability, and compatibility.

Latest run results:

Run details: (Test run date: 7 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36

Browser/OS: Chrome 57 on Windows

View result in a separate tab

Test name	Executions per second
Replace #1	4446064.5 Ops/sec
Replace #2	4458228.0 Ops/sec
Replace #3	3346879.2 Ops/sec
Replace #4	3065496.5 Ops/sec
Replace #5	2807439.8 Ops/sec

Related benchmarks:

Replace tests (version: 0)

Comparing performance of: Replace #1 vs Replace #2 vs Replace #3 vs Replace #4 vs Replace #5

Created: 7 years ago by: Guest

Jump to the latest result

Replace #1

Replace #2

Replace #3

Replace #4

Replace #5

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):