Benchmark: Array loop vs foreach vs map v2

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))
for of
for (var e of arr) { someFn(e); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map
for of

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 its test cases.

**What is being tested?**

MeasureThat.net is testing four different ways to iterate over an array in JavaScript:

1. **Array Loop**: A traditional `for` loop that manually increments an index variable to access each element in the array.
2. **`forEach` Method**: The `forEach` method, which allows you to iterate over an array and execute a callback function for each element.
3. **`map` Function**: The `map` function, which creates a new array by applying a transformation function to each element of the original array.
4. **`for...of` Loop**: A newer loop syntax introduced in ECMAScript 2015, which allows you to iterate over an iterable object (such as an array) using a simple and concise syntax.

**Options compared**

Each test case is comparing one specific implementation of iteration against the others:

* `foreach` vs `for`: This comparison tests how much faster or slower each method is when iterating over an array.
* `map` vs `for`: This comparison tests how much faster or slower the `map` function is compared to a traditional loop for transforming an array.
* `for...of` vs `for`: This comparison tests how much faster or slower the new `for...of` loop syntax is compared to the older `for` loop.

**Pros and Cons**

Here's a brief summary of each iteration method:

1. **Array Loop**: Pros: highly efficient, flexible, and easy to use. Cons: verbose, error-prone when dealing with large arrays or complex logic.
2. **`forEach` Method**: Pros: concise, easy to read, and suitable for simple cases. Cons: slower than loops in many cases, may not be optimized by JavaScript engines.
3. **`map` Function**: Pros: concise, efficient for transforming arrays, and can be parallelized. Cons: returns a new array, which can lead to memory issues if dealing with large datasets.
4. **`for...of` Loop**: Pros: concise, easy to read, and optimized by modern JavaScript engines. Cons: only suitable for iterating over arrays or iterable objects.

**Library and special features**

There are no external libraries being tested in this benchmark. However, it's worth noting that the `forEach` method is a built-in method in JavaScript, while the `map` function is also native to JavaScript (although some engines may optimize it differently). The `for...of` loop is a newer syntax introduced by ECMAScript 2015.

**Special JS features**

There are no special JavaScript features being tested or used in this benchmark. However, it's worth noting that modern JavaScript engines may have additional optimizations or support for certain features not present in this benchmark.

**Alternatives**

Other alternatives to these iteration methods include:

1. **`for...in` Loop**: An older loop syntax that iterates over the properties of an object (not suitable for arrays).
2. **`reduce` Method**: A method that reduces a collection to a single value, which can be useful in certain scenarios.
3. **Generators and Iterators**: Alternative approaches to iteration using generators and iterators, which provide more control and flexibility.

Keep in mind that this benchmark is focused on comparing the performance of specific iteration methods, rather than exploring alternative approaches or libraries.

Related benchmarks:

Array loop vs foreach vs map v2 (version: 0)

Comparing performance of: foreach vs for vs map vs for of

Created: 3 years ago by: Guest

Jump to the latest result

foreach

for

map

for of

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):