Benchmark: string.charCodeAt(index) vs string[index].charCodeAt() vs +string[index]

Script Preparation code:

var str = "012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789"

Tests:

charCodeAt(300)
str.charCodeAt(300)
[0].charCodeAt()
str[0].charCodeAt()
[300].charCodeAt()
str[300].charCodeAt()
+[0]
+(str[0])
+[300]
+(str[300])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
charCodeAt(300)
[0].charCodeAt()
[300].charCodeAt()
+[0]
+[300]

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Test name	Executions per second
charCodeAt(300)	8480823.0 Ops/sec
[0].charCodeAt()	8356395.0 Ops/sec
[300].charCodeAt()	8086396.0 Ops/sec
+[0]	8344734.0 Ops/sec
+[300]	8421745.0 Ops/sec

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

LLMs can make mistakes. Check important info.

The provided JSON represents the benchmarking test cases for JavaScript microbenchmarks on MeasureThat.net.

**What is tested:**

The benchmark tests the performance of three different approaches to access the character at a specific index in a string:

1. `str.charCodeAt(index)`: This method uses the built-in `charCodeAt()` function to get the Unicode code point of the character at the specified index.
2. `str[index].charCodeAt()`: This approach accesses the string as an array and then calls `charCodeAt()` on the individual character object.
3. `+(str[index])`: This method concatenates a string containing a single character with the original string, effectively returning the Unicode code point of the character at the specified index.

**Options compared:**

The benchmark compares these three approaches to access the character at a specific index in a string:

* **Pros and cons:**
	+ `str.charCodeAt(index)`: This is the most direct and efficient approach. It's implemented by the JavaScript engine itself, which makes it fast. However, it may not be applicable for all strings (e.g., UTF-16 or UTF-32).
	+ `str[index].charCodeAt()`: This approach requires accessing the string as an array, which adds overhead. It works for any string type but is slower than the built-in method.
	+ `+(str[index])`: This method is a creative workaround that leverages the concatenation operator to get the Unicode code point of the character at the specified index. While it's simple and applicable to all strings, it may not be as efficient as the other two approaches.
* **Other considerations:**
	+ The benchmark does not account for string length, so accessing an index out of bounds will result in a RangeError or NaN (Not a Number).
	+ The performance difference between these approaches may vary depending on the specific use case and the properties of the input strings.

**Library usage:**

The `charCodeAt()` method is a built-in JavaScript function that doesn't rely on any external libraries. It's implemented by the JavaScript engine itself, which makes it fast and efficient.

**Special JS features or syntax:**

There are no special JavaScript features or syntax used in these benchmark test cases.

**Alternative approaches:**

Other possible approaches to access the character at a specific index in a string include:

* Using a library like Lodash, which provides the `getCharCodeAt()` function: `lodash.getCharCodeAt(str, index)`
* Using a custom implementation of `charCodeAt()`: `function charCodeAt(str, index) { ... }`
* Using a different method altogether, such as using bitwise operations or ASCII codes.

Keep in mind that these alternatives may not be applicable to all use cases and may have different performance characteristics compared to the built-in methods.

Related benchmarks:

string.charCodeAt(index) vs string[index].charCodeAt() vs +string[index] (version: 0)

Comparing performance of: charCodeAt(300) vs [0].charCodeAt() vs [300].charCodeAt() vs +[0] vs +[300]

Created: 3 years ago by: Guest

Jump to the latest result

charCodeAt(300)

[0].charCodeAt()

[300].charCodeAt()

+[0]

+[300]

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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