Benchmark: 'of' vs indexed charAt() to iterate characters in a string with prototype

Script Preparation code:

var testString = 'abcdefghijklmnopqrstuvwxyz';

Tests:

char of
for (char of testString) console.log(char);
indexed charAt
for (i = 0; i < testString.length; i++) console.log(String.prototype.charAt.call(testString,i));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
char of
indexed charAt

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Linux

View result in a separate tab

Test name	Executions per second
char of	7327.6 Ops/sec
indexed charAt	8432.4 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark you've provided tests two different approaches for iterating over the characters of a string in JavaScript:

1. **For-of Loop**
   ```javascript
   for (char of testString) console.log(char);
   ```

2. **Indexed charAt() Method**
   ```javascript
   for (i = 0; i < testString.length; i++) console.log(String.prototype.charAt.call(testString, i));
   ```

### Comparison of Approaches

#### 1. For-of Loop
- **Pros:**
  - **Simplicity:** The syntax is straightforward and easy to read. It abstracts away the index handling, allowing developers to focus solely on the character being processed.
  - **Directness:** Directly iterates over the values of the iterable, making it less prone to errors (e.g., accidentally misusing the index).
  
- **Cons:**
  - **Performance:** In certain environments or with specific string lengths, it may not be as performant as indexed access, particularly in older versions of JavaScript engines.

#### 2. Indexed charAt() Method
- **Pros:**
  - **Control:** Provides explicit control over indexing, allowing for modifications or complex behaviors that might require knowledge of the character positions.
  - **Potentially Better Performance:** In some cases, especially with older JavaScript engines, using indexed access can outperform the for-of loop.

- **Cons:**
  - **Clarity:** The syntax is less intuitive than using for-of, making it harder for those unfamiliar with JavaScript to understand. It introduces complexity with handling indices.
  - **Verbosity:** Requires more code and can lead to mistakes with index calculations.

### Benchmarks Results Overview
From the benchmark results:
- The **indexed charAt** approach achieved **8432.35 executions per second**, while the **for-of** loop had **7327.60 executions per second**. This indicates that in this test case, the indexed charAt approach outperformed the for-of loop.

### Considerations
- **JavaScript Version:** Performance characteristics can vary significantly based on the JavaScript engine and its version. The latest versions of JavaScript engines (e.g., V8 for Chrome) might optimize newer constructs like for-of.
- **Use Cases:** For a one-off iteration where readability and simplicity are more valuable than the micro-optimizations of performance, the for-of loop is preferable. In performance-critical applications, profiling different methods is essential to choose the best one.

### Alternatives
Beyond the two methods benchmarked, there are other alternatives for iterating over strings, such as:
- **For Loop with Array Iteration:** Convert the string to an array using `Array.from(testString)` or the spread operator `[...testString]`, and then use a traditional `for` or `forEach` loop.
- **String.prototype.split:** You can split a string into an array of characters and iterate over them.
  
Each method has its use cases depending on the requirements of clarity, performance, and compatibility with various JavaScript engines. Ultimately, choosing the right method should be a balance between performance metrics and code maintainability.

Related benchmarks:

'of' vs indexed charAt() to iterate characters in a string with prototype (version: 1)

Comparing performance of: char of vs indexed charAt

Created: one year ago by: Guest

Jump to the latest result

char of

indexed charAt

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):