Benchmark: for vs forEach - MeasureThat.net

Script Preparation code:

var testArray = [];

for (var i = 1; i <= 1000; i++) {
   testArray.push(i);
}

Tests:

for loop
for(var i = 0; i < testArray.length; i += 1) { testArray[i] += 1; }
forEach
testArray.forEach((item) => { item += 1; });
Map
testArray.map((item) => { item += 1; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for loop
forEach
Map

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares three approaches: traditional `for` loop, `forEach`, and `map`. The test case is designed to iterate over an array of 1000 elements and perform a simple operation (incrementing each element) on each element.

**Options Compared**

1. **Traditional `for` Loop**: This approach uses a traditional `for` loop with an iterator (`i`) that iterates over the array indices.
2. **`forEach` Method**: This approach uses the `forEach` method, which is a built-in array method that executes a callback function for each element in the array.
3. **`map` Method**: This approach uses the `map` method, which returns a new array with the results of applying a provided function to every element in the original array.

**Pros and Cons**

* **Traditional `for` Loop**:
	+ Pros: Generally faster, more efficient, and easier to understand for small loops.
	+ Cons: Can be verbose, especially for larger loops. Requires manual incrementation of the iterator index.
* **`forEach` Method**:
	+ Pros: Concise, easy to read, and expressive. Eliminates the need to manually manage indices.
	+ Cons: May incur overhead due to function call and return values. Can be slower than traditional `for` loops for large arrays.
* **`map` Method**:
	+ Pros: Returns a new array with transformed elements, eliminating the need for indexing and manual incrementation. Can be faster than `forEach` for large arrays.
	+ Cons: Creates a new array, which can consume more memory. May incur overhead due to function call and return values.

**Library Used**

There is no library used in this benchmark. The code relies on built-in JavaScript methods (`for`, `forEach`, and `map`) and arrays.

**Special JS Feature or Syntax**

None of the approaches specifically utilize any special JavaScript features or syntax, such as async/await, promises, or ES6+ features like destructuring or template literals.

**Alternative Approaches**

Other alternatives to consider for this benchmark include:

* Using a custom iterator function with `for...of` loop
* Utilizing Web Workers or parallel processing for concurrent execution
* Employing more advanced array methods like `reduce`, `filter`, or `every`
* Implementing a custom loop using recursion or a generator function

Keep in mind that these alternatives may not be applicable to this specific use case, and their performance would depend on the specific requirements and constraints.

Latest run results:

Run details: (Test run date: 2025 years ago)

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36

Browser/OS: Chrome 63 on Windows 7

View result in a separate tab

Test name	Executions per second
for loop	3225.4 Ops/sec
forEach	548763.6 Ops/sec
Map	112814.0 Ops/sec

Related benchmarks:

for vs forEach (version: 0)

Comparing performance of: for loop vs forEach vs Map

Created: 6 years ago by: Guest

Jump to the latest result

for loop

forEach

Map

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):