Benchmark: for loop vs. .map 100k

Script Preparation code:

// Create sample data
const array = Array.from({ length: 100000 }, () => Math.floor(Math.random() * 1_000_000));

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: 3 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Windows

View result in a separate tab

Test name	Executions per second
.map	1604.0 Ops/sec
for loop	838.1 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 days ago):

LLMs can make mistakes. Check important info.

The benchmark in question is a performance comparison between two different methods of iterating through an array to apply a function to its elements: using the `.map()` method and a traditional `for` loop. The benchmark aims to determine which approach performs better when processing a large dataset of random numbers.

### Options Compared

1. **.map() Method**
   - **Benchmark Definition**: `var newArray = array.map( i => manipulateFn(i));`
   - **Description**: The `.map()` method is a built-in JavaScript array function that creates a new array populated with the results of calling a provided function on every element in the calling array.
   - **Pros**:
     - **Conciseness**: The `.map()` method results in cleaner and more readable code, as it abstracts the loop logic and is declarative.
     - **Functional Programming**: It allows for a functional programming style, which can be easier to understand for developers familiar with such paradigms.
   - **Cons**:
     - **Performance Overhead**: Because `.map()` involves a higher-level abstraction, there can be some performance overhead compared to low-level looping constructs, especially in large arrays.
   
2. **for Loop**
   - **Benchmark Definition**: 
     ```javascript
     var newArray = [];
     for (let i = 0; i < array.length; i++) {
         newArray.push(manipulateFn(array[i]));
     }
     ```
   - **Description**: The traditional `for` loop iterates through the index of the array, allowing for operations to be performed on each element.
   - **Pros**:
     - **Performance**: In many cases, traditional loops can be faster than higher-order functions like `.map()`, particularly in scenarios where performance is critical and the overhead of function calls is noticeable.
     - **Fine-grained control**: Developers have precise control over the iteration process, which can be optimized further if needed.
   - **Cons**:
     - **Verbosity**: Code can be more verbose and harder to read or maintain due to its imperative nature.
     - **Error-prone**: It requires careful management of the loop counter and the new array, which can introduce bugs if not handled properly.

### Library Used

In this benchmark scenario, no external libraries are used, as the operations are purely based on native JavaScript capabilities.

### Special JS Features or Syntax

The benchmark uses arrow functions in the `.map()` method:
- **Arrow Functions**: `i => manipulateFn(i)` is a concise syntax to create functions. Arrow functions are a feature introduced in ES6 (ECMAScript 2015) that provide a more succinct way to write functions, automatically binding the `this` value, and offering a cleaner syntax for function expressions.

### Alternatives

1. **forEach()**: Another array method similar to `.map()`, but it does not return a new array. It simply executes a provided function on each element without transforming the array.
   
2. **reduce()**: This method can also be used to transform data and can be a powerful alternative, though it is designed for accumulating results rather than just mapping values. It is generally more complex and can be less readable for simple transformations.

3. **While Loop**: Another traditional looping construct that offers similar performance benefits to the `for` loop but with different syntax.

4. **Function Libraries**: Libraries like Lodash or Underscore.js provide functional programming utilities that can often outperform native implementations in specific contexts while offering additional features and ease of use.

In conclusion, both the `.map()` method and the `for` loop have their regular use cases, and the decision on which one to use may depend on performance requirements, code clarity preferences, and the specific context in which the function is applied. Benchmarks such as this provide data that guide these choices via empirical evidence. In this specific case, the benchmark results show that `.map()` significantly outperforms the `for` loop in this scenario, executing over 1600 operations per second compared to about 838 for the loop. This data supports opting for `.map()` in performance-sensitive applications where the overhead difference is negligible.

Related benchmarks:

for loop vs. .map 100k (version: 1)

Comparing performance of: .map vs for loop

Created: 3 days 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 gpt-4o-mini, generated 3 days ago):