Benchmark: Performance Test: substring vs substr vs slice

Script Preparation code:

var string = "I am the god of hellfire, and I bring you..."

Tests:

slice
var substring = string.slice(17, 25);
substring
var substring = string.substring(17, 25);
substr
var substring = string.substr(17, 25);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
substring
substr

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark measures the performance of three different methods for extracting a substring from a string in JavaScript:

1. `slice()`
2. `substring()`
3. `substr()`

These methods are used to extract a portion of a string, but they differ in their implementation and usage.

**Options Compared**

Here's a brief overview of each method:

* `slice(start, end)`: Returns a new string that includes all characters from the `start` index up to (but not including) the `end` index. If `start` or `end` is negative, it counts from the start/end of the string respectively.
* `substring(start, end)`: Similar to `slice()`, but returns a new string with the specified length, without any additional characters.
* `substr(index, length)`: Returns a new string that includes all characters from the `index` position up to (but not including) the `index + length` position.

**Pros and Cons**

Here are some pros and cons of each method:

* `slice()`:
	+ Pros: Fastest, most efficient way to extract a substring. It uses native JavaScript functions.
	+ Cons: May not be suitable for very large strings or negative indices.
* `substring()`: 
	+ Pros: More readable than `slice()` and allows for specifying the length of the substring.
	+ Cons: May be slower than `slice()` due to additional checks.
* `substr()`:
	+ Pros: Similar to `substring()`, but more concise.
	+ Cons: Less readable, and some older browsers may not support it.

**Library Usage**

None of the provided methods rely on external libraries.

**Special JS Features or Syntax**

There are no specific JavaScript features or syntax being tested in this benchmark. However, the use of negative indices (`slice(-17, -25)` is not shown in the test cases, but if present, it would be handled by the `slice()` method).

**Other Alternatives**

If you need to extract a substring from a string, some other alternatives include:

* Using regular expressions (`/regex/.exec(string)`)
* Using the `indexOf()` and `substring()` methods together (`string.substring(string.indexOf('substring') + 1))`
* Using a library like jQuery's `.substr()` method

Note that these alternatives may have different performance characteristics and use cases.

In summary, this benchmark measures the performance of three different methods for extracting a substring from a string in JavaScript. The `slice()` method is generally considered the fastest and most efficient way to achieve this, but it requires careful handling of negative indices.

Latest run results:

Run details: (Test run date: 3 days ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser/OS: Firefox 132 on Ubuntu

View result in a separate tab

Test name	Executions per second
slice	1076876544.0 Ops/sec
substring	850584064.0 Ops/sec
substr	1124941568.0 Ops/sec

Related benchmarks:

Performance Test: substring vs substr vs slice (version: 0)

Comparing performance of: slice vs substring vs substr

Created: 6 years ago by: Registered User

Jump to the latest result

slice

substring

substr

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):