Benchmark: Performance Test: substring vs substr vs slice vs split for date

Script Preparation code:

var string = "2022-11-14T00:55:31.820Z"

Tests:

slice
var substring = string.slice(0, 10)
substring
var substring = string.substring(0, 10);
substr
var substring = string.substr(0, 10);
split
var substring = string.split('T')[0];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring
substr
split

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided benchmark measures the performance of different JavaScript methods for extracting substrings from a string: `slice`, `substring`, `substr`, and `split`. The test case uses a sample date string to create multiple benchmarks.

**Tested Options**

1. **`slice()`**: This method returns a new string that contains only the characters up to, but not including, the specified index.
2. **`substring()`**: This method returns a new string that contains only the characters from the start index (inclusive) to the end index (exclusive).
3. **`substr()`**: This method is an older version of `substring()`, returning a new string with the start and length specified, but without the exclusive end index.
4. **`split()`**: This method splits the string into an array of substrings, using the specified separator.

**Pros and Cons of Each Approach**

*   **`slice()`**:
    *   Pros: Efficient use of memory (returns a new string) and doesn't modify the original string.
    *   Cons: Returns only characters up to the index, not including it. May be slower if `index` is near the end of the string.
*   **`substring()`**: 
    *   Pros: Returns the desired substring with inclusion/exclusion of the start/end indices.
    *   Cons: May be slower than `slice()` due to more operations (string concatenation and index calculations).
*   **`substr()`**:
    *   Pros: Simple implementation, efficient memory usage like `substring()`.
    *   Cons: Only supports length and doesn't allow end index specification. May be outdated compared to modern JavaScript.
*   **`split()`**:
    *   Pros: Useful for parsing strings with separators (e.g., CSV or JSON data).
    *   Cons: Returns an array of substrings, which may require additional processing.

**Library Usage**

In this benchmark, no libraries are explicitly used. However, the `slice()`, `substring()`, and `substr()` methods are part of the JavaScript Standard Library.

**Special JS Features/Syntax**

None mentioned in the provided code.

**Other Alternatives**

If you're looking for alternative substring extraction methods or need to compare performance with other approaches:

1.  **`indexOf()`**: Not recommended due to its lower efficiency compared to `slice()`, `substring()`, and `substr()`.
2.  **Regular expressions (`regex`)**: Can be used to extract substrings using the `match()` method, which is more complex than the methods tested in this benchmark.

You can explore these alternatives by experimenting with different JavaScript methods and libraries on [MeasureThat.net](http://www.measurethat.net/) or other online platforms.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36

Browser/OS: Chrome 115 on Windows

View result in a separate tab

Test name	Executions per second
slice	32305546.0 Ops/sec
substring	25611742.0 Ops/sec
substr	16936544.0 Ops/sec
split	10164777.0 Ops/sec

Related benchmarks:

Performance Test: substring vs substr vs slice vs split for date (version: 0)

Comparing performance of: slice vs substring vs substr vs split

Created: one year ago by: Guest

Jump to the latest result

slice

substring

substr

split

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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