Benchmark: first and last character

Tests:

substring
let str = "example"; let newStr = str.substring(1, str.length - 1); console.log(newStr);
slice
let str = "example"; let newStr = str.slice(1, -1); console.log(newStr);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
substring
slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

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I'll break down the provided benchmarking test cases and explain what's being tested, compared, and the pros and cons of different approaches.

**Benchmark Definition**

The benchmark definition is the JSON object that defines the test case:
```json
{
    "Name": "first and last character",
    "Description": null,
    "Script Preparation Code": null,
    "Html Preparation Code": null
}
```
This definition specifies a simple test case where we create a string `str` containing the characters `"example"`, then extract the first and last characters using either `substring()` or `slice()`. The extracted characters are logged to the console.

**Individual Test Cases**

The benchmark has two individual test cases:
```javascript
[
    {
        "Benchmark Definition": "let str = \"example\";\r\nlet newStr = str.substring(1, str.length - 1);\r\nconsole.log(newStr);",
        "Test Name": "substring"
    },
    {
        "Benchmark Definition": "let str = \"example\";\r\nlet newStr = str.slice(1, -1);\r\nconsole.log(newStr);",
        "Test Name": "slice"
    }
]
```
Both test cases perform the same operation: extracting the first and last characters from the `str` string. The difference lies in the implementation:

*   **Substring()**: `str.substring(1, str.length - 1)` extracts a substring starting at index 1 (the second character) to the end of the string minus one character.
*   **Slice()**: `str.slice(1, -1)` extracts a slice of the string from index 1 to the end of the string minus one character.

**Comparison**

The benchmark is comparing the performance of `substring()` and `slice()` in this specific test case. This comparison can help identify which method is faster for extracting substrings in JavaScript.

**Pros and Cons**

*   **Substring()**:
    *   Pros: Generally more intuitive, especially when working with strings.
    *   Cons: May be slower than `slice()` because it creates a new string object by copying the original string's characters.
*   **Slice()**:
    *   Pros: Can be faster since it only returns a reference to the original string object instead of creating a new copy.
    *   Cons: Less intuitive, especially for those unfamiliar with the `slice()` method.

**Library**

None.

**Special JS Features/Syntax**

No special JavaScript features or syntax are used in these test cases. The focus is on the basic operations of substring and slice.

**Other Alternatives**

For this specific use case, other alternatives to `substring()` and `slice()` might include:

*   Using the `indexOf()` method to find the index of the first occurrence of a character, then using that index to extract the desired substring.
*   Using regular expressions (regex) to extract substrings.
*   Using a library like Lodash or Underscore.js for utility functions.

However, these alternatives might not provide significant performance improvements over `substring()` and `slice()`, especially considering their simple and intuitive usage.

Related benchmarks:

first and last character (version: 0)

Comparing performance of: substring vs slice

Created: 3 years ago by: Guest

Jump to the latest result

substring

slice

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):