Benchmark: lookup vs charAt

Script Preparation code:

var foo = 'foo'

Tests:

foo[0]
foo[0]
foo.charAt(0)
foo.charAt(0)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foo[0]
foo.charAt(0)

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/95.0.4636.0 Safari/537.36 Edg/95.0.1015.0

Browser/OS: Chrome 95 on Windows

View result in a separate tab

Test name	Executions per second
foo[0]	10466474.0 Ops/sec
foo.charAt(0)	9221082.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this JavaScript microbenchmark.

**What is tested:**
The benchmark tests two approaches to accessing the first character of a string:

1. `foo[0]` (direct array indexing)
2. `foo.charAt(0)` (method call on the `charAt()` function)

**Options compared:**

* Direct array indexing (`foo[0]`) vs.
* Method call on the `charAt()` function (`foo.charAt(0)`)

**Pros and cons of each approach:**

* **Direct array indexing (`foo[0]`):**
	+ Pros:
		- Typically faster, as it's a simple array access operation
		- Less overhead compared to method calls
	+ Cons:
		- May not be supported in all browsers or environments (e.g., older versions of Internet Explorer)
* **Method call on the `charAt()` function (`foo.charAt(0)`):**
	+ Pros:
		- More readable and maintainable, as it clearly conveys the intent of accessing a character at a specific position
		- May be more reliable in edge cases (e.g., null or undefined strings)
	+ Cons:
		- Typically slower than direct array indexing due to the overhead of method calls

**Other considerations:**

* The benchmark only tests the first character of the string, so the results may not generalize to longer strings or other access patterns.
* The use of `foo` as a variable name might be considered less readable or less idiomatic in some contexts.

**Library usage:**
There is no library explicitly mentioned in this benchmark. However, it's worth noting that `charAt()` and `indexOf()` (not shown in the provided code) are built-in methods of the String prototype in JavaScript, so they don't require any external libraries to be used.

**Special JS feature or syntax:**
The benchmark doesn't use any special JavaScript features or syntax. It only uses standard JavaScript variables, data types, and control structures.

**Alternatives:**

If you wanted to test other approaches to accessing a character in a string, you might consider adding additional benchmark cases, such as:

* Using `substring()` (e.g., `foo.substring(0, 1)`)
* Using regular expressions (e.g., `\d` or `[a-zA-Z]`)
* Using Unicode code points (e.g., `\u0041`)

However, these alternatives might not be directly comparable to the original two cases being benchmarked, as they may introduce additional overhead or have different performance characteristics.

Keep in mind that JavaScript engines and browsers are constantly evolving, so it's essential to test and benchmark different approaches to ensure you're using the most efficient and reliable methods for your specific use case.

Related benchmarks:

lookup vs charAt (version: 0)

Comparing performance of: foo[0] vs foo.charAt(0)

Created: 3 years ago by: Guest

Jump to the latest result

foo[0]

foo.charAt(0)

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):