Benchmark: slice vs substring with specified start and end

Script Preparation code:

var example = '2020-03-19T00:00:00'

Tests:

slice
var result = example.slice(0,6)
substring
var result = example.substring(0,6)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring

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 provided JSON data and explain what's being tested, the different approaches compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark definition is a simple JavaScript code snippet that defines two functions: `slice` and `substring`. Both functions are used to extract a subset of characters from a string. The specific implementation details are not provided in the benchmark definition, so we'll have to infer them based on the provided test cases.

**Script Preparation Code**

The script preparation code is a single line that defines a variable `example` with the value `'2020-03-19T00:00:00'`. This variable will be used as input for both the `slice` and `substring` functions.

**Individual Test Cases**

There are two test cases:

1. **slice**: The benchmark definition is `var result = example.slice(0,6)`, which attempts to extract 6 characters from the beginning of the `example` string.
2. **substring**: The benchmark definition is `var result = example.substring(0,6)`, which also attempts to extract 6 characters from the beginning of the `example` string.

**Comparison**

The two test cases compare the performance of the `slice` and `substring` methods for extracting a subset of characters from a string. Both methods are part of the ECMAScript standard and have similar syntax, but they work differently under the hood.

**Approach 1: String.prototype.slice()**

The `slice()` method returns a new string that is a subset of the original string. It uses the following steps:

* Takes two arguments: `start` and `end`, which define the range of characters to extract.
* Creates a new string by copying the characters from the original string, starting at the `start` index and ending at the `end` index (exclusive).
* Returns the new string.

Pros:

* More efficient than `substring()` because it doesn't create an intermediate string object.
* Can be more flexible when working with large strings or performance-critical code.

Cons:

* May not work correctly for negative indices or when `start` is greater than `end`.
* May be slower on older browsers that don't support this method.

**Approach 2: String.prototype.substring()**

The `substring()` method returns a new string that is a subset of the original string. It uses the following steps:

* Takes two arguments: `start` and `end`, which define the range of characters to extract.
* Creates an intermediate string object by copying the characters from the original string, starting at the `start` index and ending at the `end` index (exclusive).
* Returns a reference to the new string object.

Pros:

* Works correctly for negative indices or when `start` is greater than `end`.
* May be faster on older browsers that don't support this method.

Cons:

* Creates an intermediate string object, which can be slower and more memory-intensive.
* May not be suitable for large strings or performance-critical code.

**Library Usage**

In the provided benchmark definition, there is no explicit library usage. However, it's worth noting that `slice()` and `substring()` are built-in methods of the String prototype in JavaScript.

**Special JS Feature/Syntax**

There are no special JS features or syntax used in this benchmark. The code snippets are straightforward and follow standard ECMAScript syntax.

**Other Alternatives**

If you need to extract a subset of characters from a string, there are other alternatives:

* Use a regular expression with the `match()` method: `var result = example.match(/2020-03-\d\d/)[0]`.
* Use a library like `lodash` or `underscore`, which provide utility functions for string manipulation.
* Use a string slicing library like `string-slice`.

Keep in mind that these alternatives may have different performance characteristics and use cases compared to the built-in `slice()` and `substring()` methods.

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/111.0.0.0 Safari/537.36

Browser/OS: Chrome 111 on Windows

View result in a separate tab

Test name	Executions per second
slice	9607005.0 Ops/sec
substring	10184108.0 Ops/sec

Related benchmarks:

slice vs substring with specified start and end (version: 0)

Comparing performance of: slice vs substring

Created: one year ago by: Guest

Jump to the latest result

slice

substring

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):