Benchmark: Array loop vs foreach vs map real case

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 1000; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map

Fastest: N/A

Slowest: N/A

Latest run results:

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

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**Benchmark Description**

The provided benchmark tests three different approaches to iterate over an array: `foreach`, `for` loops, and `map`. The benchmark creates an array `arr` with 1000 elements, each initialized to its index value using a function `someFn(i) = i * 3 * 8`.

**Options Compared**

The benchmark compares the performance of three options:

1. **Foreach**: Iterates over the array using the `forEach` method, which calls the provided callback function once for each element in the array.
2. **For loops**: Iterates over the array using a traditional `for` loop, where the index is manually incremented and used to access elements in the array.
3. **Map**: Applies the `map` method to the array, which creates a new array with the results of applying the provided function to each element in the original array.

**Pros and Cons**

Here's a brief overview of the pros and cons for each approach:

1. **Foreach**
	* Pros: Easy to read and maintain, concise syntax.
	* Cons: May incur additional overhead due to the need to create an intermediate array or manipulate elements.
2. **For loops**
	* Pros: Direct control over iteration, no additional data structure required.
	* Cons: More verbose, error-prone due to index management.
3. **Map**
	* Pros: Concise syntax, eliminates manual iteration and indexing overhead.
	* Cons: May incur additional memory allocation for the resulting array, as it creates a new array.

**Library**

The `map` method uses the Array.prototype.map() method, which is a built-in JavaScript function that applies a provided function to each element of an array and returns a new array with the results. The purpose of this library is to provide a concise and efficient way to transform arrays by applying a function to each element.

**Special JS Feature or Syntax**

The benchmark does not use any special JavaScript features or syntax, making it accessible to a wide range of developers.

**Other Alternatives**

If you're interested in exploring alternative approaches for similar use cases:

* **Reduce**: Instead of `map`, you could use the Array.prototype.reduce() method to accumulate values. This approach is useful when you need to compute a single result from an array.
* **Set**: If you only need to iterate over unique elements, consider using the Set data structure and its methods (e.g., Set.prototype.forEach(), Set.prototype.values()).

Related benchmarks:

Array loop vs foreach vs map real case (version: 0)

Comparing performance of: foreach vs for vs map

Created: 2 years ago by: Guest

Jump to the latest result

foreach

for

map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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