Benchmark: Performance Test: substring vs slice

Script Preparation code:

var string = "testing testing 1 2 3.mp3"

Tests:

slice
var substring = string.slice(0, -4);
substring
var substring = string.substring(0, string.length-4);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2.1 Safari/605.1.15

Browser/OS: Safari 17 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
slice	21080266.0 Ops/sec
substring	11911243.0 Ops/sec

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 and explain what's being tested.

**Benchmark Overview**

The test measures the performance difference between using `slice()` and `substring()` methods to extract a substring from a string in JavaScript.

**Options Compared**

Two options are compared:

1. **`string.slice(0, -4)`**: This method creates a new string by extracting 4 characters from the end of the original string.
2. **`string.substring(0, string.length-4)`**: This method also extracts 4 characters from the end of the original string.

**Pros and Cons**

* **`slice()` method**:
	+ Pros: more efficient because it uses a single function call and creates a new array object with the desired length.
	+ Cons: may not be as intuitive for developers who are used to using `substring()`, and some older browsers may not support it.
* **`substring()` method**:
	+ Pros: widely supported by most browsers, including older ones, making it more accessible to a broader audience.
	+ Cons: slower because it involves two separate function calls (one for the start index and one for the end index), creating an intermediate string object.

**Library and Purpose**

There is no explicit library mentioned in the benchmark definition or test cases. However, both methods (`slice()` and `substring()`) are built-in JavaScript methods that come with the language itself.

**Special JS Feature or Syntax**

The benchmark uses a special feature of modern JavaScript: template literals (the `var string = "testing testing 1 2 3.mp3";` line). Template literals allow you to embed expressions inside string literals, which can make code more readable and efficient. However, this is not specific to the comparison between `slice()` and `substring()`, but rather a feature of modern JavaScript in general.

**Other Alternatives**

While the benchmark compares two methods, there are other alternatives for extracting substrings from strings:

* Using regular expressions (e.g., `string.match(/.*[^\w]/)[0]` to extract all non-word characters).
* Using arrow functions or anonymous functions with `slice()` or `substring()`.
* Using a library like Lodash (which has a `substring()` function).

In summary, the benchmark measures the performance difference between using `slice()` and `substring()` methods for substring extraction in JavaScript. The choice between these two options depends on factors such as compatibility, readability, and performance requirements.

Related benchmarks:

Performance Test: substring vs slice (version: 0)

Comparing performance of: slice vs substring

Created: 2 years ago by: Guest

Jump to the latest result

slice

substring

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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