Benchmark: for loop vs. .map

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));
for loop
var newArray = []; for (let i=0; i<array.length; i++) { newArray.push(manipulateFn(array[i])); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
.map
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
.map	24678486.0 Ops/sec
for loop	16904446.0 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 provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is comparing two approaches: using the `.map()` method versus a traditional `for` loop to perform an operation on an array of numbers. The operation involves multiplying each number by 2 and then by 3, as defined in the `manipulateFn` function.

**Options Compared**

Two options are being compared:

1. **`.map()`**: This is a built-in JavaScript method that applies a transformation to each element of an array and returns a new array with the transformed elements.
2. **Traditional `for` loop**: A classic way to iterate over an array, using a counter variable (`i`) to access each element.

**Pros and Cons**

**`.map()`**:

Pros:

* concise and expressive
* easy to read and understand
* can be more efficient for small arrays

Cons:

* can be slower for large arrays due to the overhead of function calls and array manipulation
* requires an additional function call, which can introduce overhead

**Traditional `for` loop**:

Pros:

* often faster for large arrays due to better caching and fewer function calls
* can be more efficient in terms of memory usage (no need to create a new array)

Cons:

* can be verbose and harder to read, especially for complex loops
* requires manual management of the counter variable and loop termination

**Other Considerations**

In this benchmark, the focus is on measuring the execution speed of each approach. Other factors like memory usage, code readability, and maintainability might also be worth considering in a real-world scenario.

**Library Used (if any)**

None mentioned in the provided JSON.

**Special JS Features or Syntax (if applicable)**

`.map()` uses a feature called **"arrow functions"**, which were introduced in ECMAScript 2015. These are concise ways to define small, anonymous functions using the `=>` operator. Traditional `for` loops do not use this syntax.

**Alternative Approaches**

If you want to explore alternative approaches, here are a few:

1. **Using `forEach()` instead of `.map()```**: While similar to `.map()`, `forEach()` doesn't return a new array and can be faster for large arrays.
2. **Using `reduce()` instead of traditional loops**: If you need to accumulate values or perform more complex operations, `reduce()` can be a good alternative.
3. **Using modern JavaScript features like `async/await` or `Promises```**: These might offer better performance and concurrency advantages in certain scenarios.

Keep in mind that the optimal approach depends on your specific use case and requirements.

Related benchmarks:

for loop vs. .map (version: 0)

Comparing performance of: .map vs for loop

Created: 5 years ago by: Guest

Jump to the latest result

.map

for loop

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):