Benchmark: For Each Vs Map Example Medium 2

Script Preparation code:

// Create sample data
var array = [1,2,3,4,5,6,7,8,9,0];

var manipulateFn = num => {
	return num * 2 * 3;
}

Tests:

.map
var newArray = array.map( i => manipulateFn(i));
.forEach
var newArray = []; array.forEach( i => { newArray.push(manipulateFn(i)); });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.map
.forEach

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Windows

View result in a separate tab

Test name	Executions per second
.map	19687412.0 Ops/sec
.forEach	36138812.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Overview**

The benchmark is designed to compare the performance of two approaches: `map()` and `forEach()` methods in JavaScript, which are used to iterate over an array and perform an operation on each element. The benchmark is written in JavaScript and uses a simple example where an array of numbers is manipulated by multiplying each number by 2 and then by 3.

**Options Compared**

The two options being compared are:

1. `map()`: This method creates a new array with the results of applying a provided function to every element in the calling array.
2. `forEach()`: This method executes a callback function once for each element in an array, and returns no value.

**Pros and Cons**

* **Map()**:
	+ Pros: Efficient way to create a new array by transforming existing elements.
	+ Cons: Creates a new array, which can be memory-intensive for large datasets. Also, the order of the original array is preserved.
* `forEach()`:
	+ Pros: Does not create a new array, making it memory-efficient.
	+ Cons: Returns no value (i.e., `undefined`), and does not preserve the order of the original array.

**Library and Special JavaScript Features**

In this benchmark, there are no explicit libraries being used. However, some features of modern JavaScript are employed:

* Arrow functions (`num => { ... }`) are used to define small anonymous functions.
* The spread operator (`...`) is implied but not explicitly used in the code; it would be used if you wanted to create a new array from an existing one.

**Considerations**

When deciding between `map()` and `forEach()`, consider the following:

* If you need to preserve the original order of the array, use `map()`.
* If memory efficiency is critical and the order of the array doesn't matter, use `forEach()`.

**Other Alternatives**

If you want to explore other alternatives, here are a few options:

* **Reduce()**: This method reduces an array to a single value by applying a function to each element.
* **For...of` loop: This is a more traditional way of iterating over arrays in JavaScript, using a `for...of` loop with the `Array.prototype.forEach()` method as its body.

These alternatives might be used in different benchmarking scenarios or production code.

Related benchmarks:

For Each Vs Map Example Medium 2 (version: 0)

Comparing performance of: .map vs .forEach

Created: 7 years ago by: Guest

Jump to the latest result

.map

.forEach

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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