Benchmark: (last character) char index vs charAt() vs slice()

Script Preparation code:

var str = 'zab rab oof';
var noop = Function.prototype;

Tests:

character index
if (str[str.length-1] == 'f') noop();
charAt()
if (str.charAt(str.length-1) == 'f') noop();
slice()
if (str.slice(-1) == 'f') noop();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
character index
charAt()
slice()

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, the options compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark is designed to compare three methods for accessing the first character of a string: `str[str.length-1]`, `str.charAt(str.length-1)`, and `str.slice(-1)`.

**Options Compared**

The three options are compared in terms of their performance, which is measured by the number of executions per second.

**Pros and Cons**

* **Character Index (str[str.length-1])**:
	+ Pros: Simple and straightforward. Does not require a separate function call.
	+ Cons: May be slower than other methods due to string slicing or indexing.
* **CharAt() (str.charAt(str.length-1))**:
	+ Pros: More readable and maintainable than character index. Provides a way to access characters in strings.
	+ Cons: Requires a separate function call, which may introduce overhead.
* **Slice(-1) (str.slice(-1))**:
	+ Pros: Similar performance to charAt() due to browser optimization for string slicing.
	+ Cons: May require more memory allocation compared to character index.

**Library and Its Purpose**

None of the options in this benchmark use a specific library. However, the `noop()` function is used as a no-op (no operation) to prevent the browser from optimizing away the test case.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark.

**Other Considerations**

* The benchmark uses a relatively short string (`'zab rab oof'`) to minimize the impact of memory allocation and garbage collection.
* The `noop()` function is used as a placeholder to prevent browser optimizations from affecting the test results.
* The benchmark does not account for edge cases, such as empty strings or null inputs.

**Alternatives**

Other alternatives to compare in string manipulation benchmarks could include:

* Using `substr` instead of character index or slice
* Using regular expressions to access characters
* Comparing performance with different data types (e.g., numbers, arrays)
* Testing edge cases, such as null or undefined inputs

Keep in mind that the specific options and alternatives will depend on the requirements and goals of the benchmark.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36 Edg/88.0.705.68

Browser/OS: Chrome 88 on Windows

View result in a separate tab

Test name	Executions per second
character index	5272042.0 Ops/sec
charAt()	5205167.5 Ops/sec
slice()	7391602.0 Ops/sec

Related benchmarks:

(last character) char index vs charAt() vs slice() (version: 0)

Compare methods for testing string's beggining character.

Comparing performance of: character index vs charAt() vs slice()

Created: 3 years ago by: Guest

Jump to the latest result

character index

charAt()

slice()

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):