Benchmark: Basic array iterations

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

foreach
arr.forEach(function (item){ someFn(item); })
for
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }
map
arr.map(item => someFn(item))
for in
for (let index in arr) { someFn(arr[index]) }
for of
for (const item of arr) { someFn(item) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
for in
for of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Linux; Android 10; Redmi Note 8 Pro) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.120 Mobile Safari/537.36

Browser/OS: Chrome Mobile 91 on Android

View result in a separate tab

Test name	Executions per second
foreach	3573.2 Ops/sec
for	2011.3 Ops/sec
map	3694.5 Ops/sec
for in	1646.5 Ops/sec
for of	3926.2 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark tests four different ways to iterate over an array of numbers:

1. `forEach`
2. `for` loop
3. `map`
4. `for...of` loop

Each test case uses a custom function, `someFn`, which takes an argument and returns the result of multiplying it by 3 and then by 8.

**Options Comparison**

Here's a brief overview of each option:

1. **`forEach"`**: This method iterates over the array using the callback function provided in the test case definition.
	* Pros: Simple, easy to understand, and well-documented.
	* Cons: May not be optimized for performance, as it uses a separate loop mechanism.
2. **`for` loop**: This traditional loop iterates over the array indices directly.
	* Pros: Fast and efficient, as it uses native CPU instructions.
	* Cons: Can be harder to understand, especially for developers without prior experience with JavaScript.
3. **`map()`**: This method creates a new array by applying the callback function to each element in the original array.
	* Pros: Allows for functional programming style, which can lead to more concise and readable code.
	* Cons: May create a new array, which could be memory-inefficient if not optimized.
4. **`for...of` loop**: This modern loop iterates over the array elements directly, similar to `forEach`, but with improved readability.
	* Pros: Modern and efficient, as it uses native CPU instructions.
	* Cons: May still require some understanding of the new syntax.

**Library Usage**

The benchmark doesn't use any external libraries for this test. However, if you wanted to add additional functionality or optimizations, you might consider using a library like:

1. **ES6 `Promise` API**: For handling asynchronous operations and improving performance.
2. **Web Workers**: For parallelizing computationally expensive tasks.

**Special JS Features/Syntax**

The benchmark uses the following special JavaScript features:

1. **Arrow functions**: Used in some test cases (e.g., `arr.map(item => someFn(item))`).
	* Introduced in ECMAScript 2015, arrow functions provide a concise syntax for creating functions.
2. **Let and const declarations**: Used in some test cases (e.g., `for (let index in arr)`).
	* Introduced in ECMAScript 2015, these declarations allow for block scope and improved code readability.

**Other Alternatives**

If you wanted to explore alternative approaches, consider the following:

1. **Native Array methods**: Instead of using custom functions or loops, you could use native Array methods like `reduce()`, `filter()`, or `every()`.
2. **Parallel processing**: Using Web Workers or libraries like `worker_threads` to execute tasks in parallel.
3. **Just-In-Time (JIT) compilation**: Using libraries like `V8` to optimize performance by compiling JavaScript code into machine code.

These alternatives might offer improved performance, but also come with additional complexity and learning curves.

Related benchmarks:

Basic array iterations (version: 0)

For of vs for in vs forEach vs map!

Comparing performance of: foreach vs for vs map vs for in vs for of

Created: 3 years ago by: Guest

Jump to the latest result

foreach

for

map

for in

for of

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):