Benchmark: slice vs substr vs substring (with end index) 2

Script Preparation code:

var example = 'there is no spoon'

Tests:

slice
var result = example.slice(0,10)
substr
var result = example.substr(0,10)
substring
var result = example.substring(0.10)

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 dive into the explanation of the provided benchmark.

**Benchmark Overview**

The benchmark compares three JavaScript methods to extract a subset of a string: `slice`, `substr`, and `substring`. The test focuses on the case where only a start index is specified, with the end index being omitted (i.e., it defaults to the end of the string).

**Methods Compared**

1. **`slice(startIndex)`**: Returns a new string containing all characters from `startIndex` to the end of the original string.
2. **`substr(startIndex)`**: Returns a new string containing all characters from `startIndex` to the end of the original string, without considering the end index (i.e., it defaults to the end of the string).
3. **`substring(startIndex)`**: Similar to `substr`, but returns only the characters from `startIndex` to the end of the substring.

**Options Compared**

The benchmark compares these three methods with different start indices:

*   `slice(0,10)`: Extracts 10 characters starting from index 0.
*   `substr(0,10)`: Extracts 10 characters starting from index 0 (same as above).
*   `substring(0.10)`: This is incorrect syntax for the `substring` method. The correct syntax would be `substring(0.10)`, which is not a valid test case.

**Pros and Cons of Each Approach**

1.  **`slice(startIndex)`**: Pros:

*   More efficient than `substr` and `substring` when the end index is known.
    *   Returns a new string, avoiding any potential side effects on the original string.
2    **`substr(startIndex)`**:

*   May be faster than `slice` because it doesn't create a new string.
    *   Less intuitive for developers who are used to Python-style slicing, which returns a view of the original array/string.
3.  **`substring(startIndex)`**: This method is not typically recommended due to its incorrect syntax and potential performance issues.

**Library Usage**

None of the provided benchmark cases use any external libraries.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax used in this benchmark except for the `substring` method with an invalid start index (0.10). This is not a valid test case, as it should be `substring(0.10)` to indicate starting from index 0.1.

**Other Alternatives**

Some alternative methods that could be tested include:

*   Using `slice()` and comparing performance with other libraries like Lodash or Ramda.
*   Comparing the performance of different string slicing approaches, such as using `substring()` with a fixed end index versus using `slice()` or `substr()`.
*   Testing the performance of these methods on different types of data structures, like arrays or objects.

To fix this invalid syntax for substring test case:

"Benchmark Definition": "var result = example.substring(0.10)"

This change ensures that the benchmark is accurately testing the behavior of the `substring()` method and avoids any potential issues with incorrect syntax.

Related benchmarks:

slice vs substr vs substring (with end index) 2 (version: 0)

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

Comparing performance of: slice vs substr vs substring

Created: 4 years ago by: Guest

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):