Benchmark: String slice vs. array slice

Script Preparation code:

var str = ""
var arr = []
for (let i = 0; i < 100000; ++i) {
    str += 'ABC::';
    arr.push('ABC');
}

Tests:

String slice
function process(s){ return s.slice(0,s.lastIndexOf(':')) } while (str.length) { str = process(str); }
Array slice
function process(a){ return a.slice(0,a.length-2) } while (arr.length) { arr = process(arr); }
Array with creation
let str = "" for (let i = 0; i < 100000; ++i) { str += 'ABC:'; } function process(a){ return a.slice(0,a.length-2) } while (arr.length) { arr = process(arr); }
String with creation
let str = "" for (let i = 0; i < 100000; ++i) { str += 'ABC:'; } function process(s){ return s.slice(0,s.lastIndexOf(':')) } while (str.length) { str = process(str); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String slice
Array slice
Array with creation
String with creation

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/113.0

Browser/OS: Firefox 113 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
String slice	153434336.0 Ops/sec
Array slice	119252856.0 Ops/sec
Array with creation	1756.4 Ops/sec
String with creation	238.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**Benchmark Overview**

The provided JSON represents a benchmark that compares three different approaches to slice strings and arrays in JavaScript:

1. **String slicing**: Using the `slice()` method on a string object (`str.slice(0, str.lastIndexOf(':'))`).
2. **Array slicing**: Using the `slice()` method on an array object (`arr.slice(0, arr.length-2)`).
3. **Creating a new array or string**: Creating a new array or string object and then slicing it (`let arr = []; for (let i = 0; i < 100000; ++i) { arr.push('ABC'); }`).

**Options Compared**

The benchmark compares the performance of these three approaches:

1. **String slicing**: Using `slice()` on a string object.
2. **Array slicing**: Using `slice()` on an array object.
3. **Creating a new array or string**: Creating a new array or string object and then slicing it.

**Pros and Cons**

Here's a brief analysis of the pros and cons of each approach:

1. **String slicing**:
	* Pros: Efficient, as it uses a built-in method to extract a substring.
	* Cons: May be slower for very large strings due to the overhead of creating a new substring object.
2. **Array slicing**:
	* Pros: Can be faster than string slicing for very large arrays, as it avoids the overhead of creating a new substring object.
	* Cons: May not be suitable for strings, as `slice()` is designed for arrays.
3. **Creating a new array or string**:
	* Pros: Can be more predictable and controllable, as the programmer has direct control over the creation and slicing of the data structure.
	* Cons: Can be slower due to the overhead of creating a new object.

**Library and Syntax Considerations**

In this benchmark, no libraries are used, and special JavaScript features (e.g., `let` and `const`) are not mentioned. However, it's worth noting that the use of `let` and `const` instead of traditional variable declarations can affect the performance of some operations.

**Other Alternatives**

Other approaches to slice strings and arrays in JavaScript might include:

1. **Substr() method**: Using the `substr()` method, which is similar to `slice()`, but returns a new string object instead of an array.
2. **Split() and join() methods**: Using the `split()` and `join()` methods to extract substrings from strings or concatenate arrays.
3. **RegExp objects**: Using regular expressions (regex) to extract substrings from strings.

Keep in mind that these alternatives might have different performance characteristics and use cases, which are not explored in this benchmark.

Related benchmarks:

String slice vs. array slice (version: 0)

Comparing performance of: String slice vs Array slice vs Array with creation vs String with creation

Created: one year ago by: Guest

Jump to the latest result

String slice

Array slice

Array with creation

String with creation

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):