Benchmark: Array loop vs foreach(with and without arrow) vs map

Script Preparation code:

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

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
foreach with arrow as well

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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Let's break down the benchmark and explain what is being tested.

**Benchmark Overview**

The benchmark measures the performance of three different approaches to iterate over an array in JavaScript:

1. **Array Loop**: A traditional for loop that manually iterates over the array using an index variable.
2. **forEach**: The `forEach` method, which is a built-in array method that calls a provided function once for each element in the array.
3. **map**: The `map` method, which returns a new array with the results of applying a provided function to each element in the original array.

**Options Compared**

The benchmark compares the performance of these three approaches:

* **Array Loop**: A traditional for loop that manually iterates over the array using an index variable.
* **forEach**: The `forEach` method, which is a built-in array method that calls a provided function once for each element in the array. There are two variations:
	+ **foreach without arrow function**: A traditional for loop with a callback function (not using arrow functions).
	+ **foreach with arrow function**: Using an arrow function as the callback function.
* **map**: The `map` method, which returns a new array with the results of applying a provided function to each element in the original array.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Array Loop**:
	+ Pros: Direct access to elements, no overhead from built-in methods.
	+ Cons: Requires manual index management, more prone to errors.
* **forEach** (with arrow function):
	+ Pros: Concise code, easy to read, less prone to errors compared to traditional for loops.
	+ Cons: May have some performance overhead due to the added layer of indirection.
* **map**:
	+ Pros: Returns a new array with transformed elements, easy to chain methods together.
	+ Cons: May have performance overhead due to creating a new array.

**Library and Special JS Features**

There is no library used in this benchmark. However, it does use the following special JavaScript features:

* **Arrow functions**: Used in the "foreach with arrow as well" variation of the `forEach` approach.
* **Built-in methods**: The `forEach` and `map` methods are built-in to the JavaScript language.

**Other Alternatives**

Other alternatives to iterate over arrays in JavaScript include:

* Using a `for...of` loop (introduced in ECMAScript 2015)
* Using `Array.prototype.reduce()`
* Using `Array.prototype.every()` or `Array.prototype.some()`

Note that each of these alternatives has its own trade-offs and use cases, and may not always be the best choice for every situation.

Related benchmarks:

Array loop vs foreach(with and without arrow) vs map (version: 0)

Comparing performance of: foreach vs for vs map vs foreach with arrow as well

Created: 5 years ago by: Guest

Jump to the latest result

foreach

for

map

foreach with arrow as well

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):