Benchmark: if slice vs substr vs substring (with no end index)

Script Preparation code:

var example = 'Hay amk ne spoonmuş';
var a = example.indexOf('spoon');

Tests:

slice
if(a !== -1){ console.log(example.toLowerCase().slice(a)) }
substr
if(a !== -1){ console.log(example.toLowerCase().substr(a)) }
substring
if(a !== -1){ console.log(example.toLowerCase().substring(a)) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substr
substring

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**

The benchmark compares three methods to extract a substring from a string: `slice`, `substr`, and `substring`. The comparison is done when there is only a start index, meaning the end index is not specified.

**Options being compared:**

1. **Slice (String.prototype.slice())**: Returns a new string containing the characters before and after the specified start index.
2. **Substr (String.prototype.substr())**: Returns the substring of the original string from the specified start index to the end of the string.
3. **Substring (String.prototype.substring())**: Returns the substring of the original string from the specified start index to the end of the string.

**Pros and Cons:**

*   `slice`:
    *   Pros: Creates a new string, which can be beneficial for memory safety and avoiding side effects in string manipulation functions.
    *   Cons: Can create an unnecessary copy of the string, potentially affecting performance.
*   `substr`:
    *   Pros: Returns the substring directly from the original string, which can improve performance by avoiding a copy operation.
    *   Cons: May cause issues if the start index is close to the end of the string, as it could lead to undefined behavior or errors.
*   `substring`:
    *   Pros: Returns the substring directly from the original string and includes the character at the specified start index, which can improve performance by avoiding a copy operation.
    *   Cons: May cause issues if the start index is greater than 0, as it could lead to undefined behavior or errors.

**Library and purpose:**

None of the test cases use any libraries. The `String.prototype` methods (`slice`, `substr`, and `substring`) are built-in methods in JavaScript that operate on strings.

**Special JS feature or syntax:**

The benchmark uses JavaScript's template literals (e.g., `\r\nvar example = 'Hay amk ne spoonmuş';\r\n...`) to create a string. This is not a special feature, but it demonstrates how JavaScript can be used to manipulate and prepare data for the benchmark.

**Other considerations:**

When writing benchmarks like this one, consider the following:

*   **Use meaningful variable names**: Using `a` as both the variable name for the index and the value of `indexOf()` might lead to confusion. Use more descriptive names to make the code easier to understand.
*   **Keep the benchmark simple**: Avoid complex logic or operations that could skew the results. Keep the focus on comparing the three methods in a straightforward way.
*   **Test for edge cases**: Consider adding test cases to cover edge scenarios, such as:
    *   When the start index is equal to 0
    *   When the start index is greater than the length of the string
    *   When the start index is negative

**Alternatives:**

If you're looking for alternatives or variations on this benchmark:

*   Compare other methods for extracting substrings, such as `indexOf()` and `slice()`.
*   Explore different use cases, like extracting a substring from an array of strings.
*   Use different data types (e.g., numbers, dates) to see how string manipulation functions behave.

Related benchmarks:

if slice vs substr vs substring (with no end index) (version: 2)

Compares slice, substr and substring to each other when there is only a start index

Comparing performance of: slice vs substr vs substring

Created: 7 years ago by: Registered User

Jump to the latest result

slice

substr

substring

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):