Benchmark: slice vs substring remove last char

Script Preparation code:

var str = 'HH:MM aa'

Tests:

slice
var strSlice = str.slice(0,-1)
substring
var strSubstr = str.substring(0, str.length-1)

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: 3 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36 Edg/143.0.0.0

Browser/OS: Chrome 143 on Windows

View result in a separate tab

Test name	Executions per second
slice	22924958.0 Ops/sec
substring	19736804.0 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 JSON data and explain what's being tested.

**Benchmark Definition**

The benchmark definition is a simple JavaScript statement that creates a variable `str` with the value `'HH:MM aa'`. This string will be used as input for the test cases.

**Test Cases**

There are two test cases:

1. `slice`: Creates a new string slice from `str`, starting from the beginning (`0`) and ending at the second-to-last character (`-1`). This effectively removes the last character of the original string.
2. `substring`: Creates a new substring from `str`, starting from the beginning (`0`) and ending at the length of the original string minus one (`str.length-1`). This also effectively removes the last character of the original string.

**Options Compared**

The two test cases are comparing the performance of using `slice` versus `substring` to remove the last character from a string. In other words, they are measuring which method is faster.

**Pros and Cons**

* **Slice**: Pros:
	+ More concise and readable.
	+ Can be used with array methods like `filter()` or `map()`.
	Cons:
	+ May not be as efficient as `substring` for very large strings due to the overhead of creating a new array.
* **Substring**: Pros:
	+ More explicit and predictable.
	+ Can be more efficient than `slice` for very large strings, since it avoids creating a new array.
Cons:
	+ Less concise and less readable.

**Library/Functionality**

Neither `slice()` nor `substring()` are libraries or functions that require special knowledge. They are built-in JavaScript methods that have been part of the language since its inception.

However, if you're using an older version of JavaScript that doesn't support these methods (e.g., Internet Explorer 8 or earlier), you may need to use a polyfill or a different approach.

**Special JS Feature/Syntax**

Neither `slice()` nor `substring()` require any special JavaScript features or syntax. They are standard built-in methods that can be used in most modern JavaScript environments.

**Other Alternatives**

If you need to remove the last character from a string, you could also use:

* String slicing with an empty substring: `str.slice(0, str.length-1)`
* String concatenation and trimming: `str + str.slice(1)`

However, these alternatives may not be as efficient or readable as using `slice()` or `substring()`.

Related benchmarks:

slice vs substring remove last char (version: 0)

Comparing performance of: slice vs substring

Created: 5 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):