Benchmark: for loop vs. .map anon

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(i *2 * 3); }

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: one month ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser/OS: Firefox 132 on Linux

View result in a separate tab

Test name	Executions per second
.map	23489034.0 Ops/sec
for loop	28523042.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the JSON is focused on comparing two different approaches to manipulating arrays in JavaScript: using the `.map()` method versus a traditional `for` loop. Here's a breakdown of what each test case assesses, the pros and cons of each approach, and some additional considerations:

### Test Cases

1. **.map() Method**
   - **Benchmark Definition**: `var newArray = array.map(i => manipulateFn(i));`
   - **Description**: This case uses the `.map()` method, which is a higher-order function that applies the `manipulateFn` function to every element in the `array`, creating a new array (`newArray`) populated with the results. The function `manipulateFn` doubles a number and multiplies it by three.

2. **For Loop**
   - **Benchmark Definition**: 
     ```javascript
     var newArray = [];
     for (let i = 0; i < array.length; i++) {
         newArray.push(i * 2 * 3);
     }
     ```
   - **Description**: This case uses a traditional `for` loop to iterate through the `array`. It pushes calculated values (each index multiplied by 2 and then by 3) into a new array. Note that there seems to be a discrepancy in the intention, as it should use `array[i]` instead of `i` for clarity.

### Performance Results
- The benchmark results exhibit the number of executions per second for each test case:
  - **For Loop**: 28,523,042 executions/second
  - **.map()**: 23,489,034 executions/second

### Pros and Cons

**.map() Method**:
- **Pros**:
  - *Readability*: The functional nature of `.map()` tends to lead to clearer and more readable code, especially for those familiar with functional programming paradigms.
  - *Chaining*: It can be easily chained with other array methods (like `.filter()`, `.reduce()`, etc.), leading to concise and expressive code.

- **Cons**:
  - *Performance*: In this benchmark, `.map()` is slower than the `for` loop, which may be a consideration in performance-critical applications.
  - *Overhead*: It might introduce slight overhead due to the creation of new functions and additional memory allocation for new arrays.

**For Loop**:
- **Pros**:
  - *Performance*: The `for` loop demonstrated superior performance in this benchmark, making it potentially more suitable for performance-critical tasks or when processing very large arrays.
  - *Flexibility*: You have more control over the iteration process and can easily manage the loop indexes, handle breaks, or conditional statements.

- **Cons**:
  - *Verbosity*: Traditional loops can be more verbose and harder to read, especially as the complexity of the operations increases.
  - *Error-prone*: There's a greater chance of off-by-one errors or forgetting to update the loop variable, which can lead to bugs.

### Other Considerations
- **Maintainability**: While the `.map()` method is typically preferred for its clarity, performance can be critical in scenarios involving a large dataset, and the choice may depend on the specific requirements of the application.
- **Alternatives**: Other alternatives to manipulate arrays in JavaScript include:
  - **`forEach()`**: Similar to `.map()`, but does not return a new array. It simply executes a provided function once for each array element.
  - **`reduce()`**: Can be used if you want to accumulate results rather than just transforming the elements, offering flexibility at the cost of a more complex syntax.
  - **`Array.from()`** or **spreading syntax**: For converting iterable objects or arrays while applying a mapping function, but may not be as performant as the traditional `for` loop.

Choosing between these methods depends on specific use cases, keeping in mind the trade-offs between performance and code clarity.

Related benchmarks:

for loop vs. .map anon (version: 1)

Comparing performance of: .map vs for loop

Created: one month 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 one month ago):