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

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

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months 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.

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 2 months ago):