Benchmark: For Loop vs For Of in iterating strings

Script Preparation code:

function validCharForL(s){
  const n='"*/:<>?\\|';
  let r="";
  for(let i=0,l=s.length;i<l;i++)
    r+=n.includes(s[i])?String.fromCharCode(s.charCodeAt(i)+65248):s[i];
  return r
};

function validCharForOf(s){
  const n='"*/:<>?\\|';
  let r="";
  for(let c of s)
    r+=n.includes(c)?String.fromCharCode(c.charCodeAt()+65248):c;
  return r
};

Tests:

For Loop
for (let i = 0; i < 1000; i++) validCharForL("1234*/:<abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234");
For Of
for (let i = 0; i < 1000; i++) validCharForOf("1234*/:<abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234abcd1234");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
For Loop
For Of

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

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Let's break down the benchmark definition and results.

**Benchmark Definition:**

The benchmark tests two different approaches for iterating through a string and replacing invalid characters for Windows and Linux:

1. **`for` loop**: The `validCharForL()` function uses a traditional `for` loop to iterate through each character of the input string, checking if it's an invalid character using the `includes()` method. If it is, the function converts it to a valid character by adding 65248 to its Unicode code point.
2. **`for...of` loop**: The `validCharForOf()` function uses an ES6-style `for...of` loop (introduced in ECMAScript 2015) to iterate through each character of the input string. It then checks if the character is invalid using the same method as above.

**Test Cases:**

Two test cases are provided:

1. **For Loop**: This test case runs the `validCharForL()` function 1000 times with a large input string.
2. **For Of**: This test case runs the `validCharForOf()` function 1000 times with the same large input string.

**Benchmark Results:**

The results show that:

1. **`for` loop**: On Chrome 107 (Linux desktop), this approach executes approximately 322.7 times per second.
2. **`for...of` loop**: On the same environment, this approach executes approximately 288.4 times per second.

**Library/Feature used:**

No external libraries are used in these test cases. However:

* The `includes()` method is part of the JavaScript standard library and checks if a character is present in a string.
* The `String.fromCharCode()` method is also part of the JavaScript standard library and converts an ASCII value to its corresponding Unicode character.

**Pro/Cons of each approach:**

Both approaches are relatively simple and efficient for small input strings. However:

* **`for` loop**: This approach has been around since ECMAScript 1 (1997) and might be more familiar to developers who have worked with older JavaScript versions.
* **`for...of` loop**: Introduced in ECMAScript 2015, this feature is more concise and expressive, making it easier to read and write. However, some older browsers or environments might not support it.

**Other Considerations:**

When choosing between these approaches:

* If performance is critical, the traditional `for` loop might be slightly faster due to its simplicity.
* For larger input strings or complex iterations, a more modern approach like `for...of` or other asynchronous iteration methods (e.g., `Promise.all()`) might be more suitable.

**Alternatives:**

Other alternatives for iterating through strings include:

* **Array.prototype.map()**: Convert each character to an array element and process it using the map method.
* **Async/Await**: Use promises and async/await syntax to iterate through a string asynchronously.
* **Modern iteration methods**: Utilize newer iteration methods like `String.prototype.split()` or `Array.prototype.reduce()`.

Related benchmarks:

For Loop vs For Of in iterating strings (version: 0)

validCharForL() and validCharForOf() iterate through a string and full-width any characters invalid for Windows and Linux, using, respectively, a for loop and a for of loop.

Comparing performance of: For Loop vs For Of

Created: 3 years ago by: Registered User

Jump to the latest result

For Loop

For Of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):