Benchmark: Array loop vs foreach vs map vs while new array

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

foreach
var newArr = [] arr.forEach(function (item){ newArr.push(someFn(item)); })
for
var newArr = [] for (var i = 0, len = arr.length; i < len; i++) { newArr.push(someFn(arr[i])); }
map
var newArr = arr.map(item => someFn(item))
while
let i = 0, len = arr.length; var newArr = [] while (i<len) { newArr.push(someFn(arr[i])); i++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
while

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases.

**Benchmark Definition**

The benchmark is designed to compare the performance of different JavaScript loops for creating a new array: `Array` loop, `for` loop, `forEach` loop, and `while` loop with a new array creation. The script preparation code creates an array of 1 million elements, each with a simple function that multiplies its value by 3 and 8.

**Test Cases**

There are four test cases:

1. **`foreach` loop**: This test case uses the `forEach` method to iterate over the array and create a new array with the same number of elements.
2. **`for` loop**: This test case uses a traditional `for` loop to iterate over the array and create a new array with the same number of elements.
3. **`map` method**: This test case uses the `map` method to create a new array by applying the multiplication function to each element in the original array.
4. **`while` loop**: This test case uses a `while` loop to iterate over the array and create a new array with the same number of elements.

**Library and Special JavaScript Features**

None of the test cases use any external libraries or special JavaScript features beyond what's included in the benchmark definition. The only notable aspect is that the `map` method is used, which is a built-in JavaScript method for creating a new array by applying a transformation function to each element.

**Performance Considerations**

When it comes to performance, the order of operations and loop structure can significantly impact execution time. Here's a brief overview of the pros and cons of each approach:

1. **`foreach` loop**: This loop is generally slower than others because it involves more overhead due to the iteration and callback function invocation.
2. **`for` loop**: A traditional `for` loop is usually faster than the other loops because it avoids the overhead of callback functions and has direct access to array elements.
3. **`map` method**: The `map` method can be slower than a simple loop, especially for large datasets, due to its creation of an intermediate array and additional function calls.

**Other Alternatives**

If you're looking for alternatives or variations on this benchmark, consider the following:

* Using other data structures like `Set`, `Queue`, or `Deque`.
* Incorporating parallel processing using Web Workers or async/await.
* Introducing more complex transformation functions or conditional statements within the loops.
* Adding noise to the input data (e.g., random values, NaNs) to simulate real-world scenarios.

**Benchmarking Insights**

The provided benchmark results show that the `while` loop is currently the fastest, followed by the `for` loop. The `map` method and `foreach` loop are slower due to their additional overhead. Keep in mind that these results may vary depending on the specific browser, version, and system configuration.

In conclusion, this benchmark provides a comprehensive comparison of different JavaScript loops for creating a new array, highlighting the importance of loop structure, callback functions, and data access patterns when optimizing performance.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:95.0) Gecko/20100101 Firefox/95.0

Browser/OS: Firefox 95 on Windows

View result in a separate tab

Test name	Executions per second
foreach	48.8 Ops/sec
for	63.3 Ops/sec
map	57.9 Ops/sec
while	63.5 Ops/sec

Related benchmarks:

Array loop vs foreach vs map vs while new array (version: 0)

Comparing performance of: foreach vs for vs map vs while

Created: 2 years ago by: Guest

Jump to the latest result

foreach

for

map

while

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):