Benchmark: for vs forEach vs for in vs for of vs lodash vs for reverse (2)

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.15/lodash.min.js"></script>

Script Preparation code:

var arr = [];

function doMath(a) {
  return Math.log(a);
}

for(i=0; i<10000; i++){
  arr[i] = i + 1;
}

Tests:

forEach
let sum = 0; arr.forEach((value) => { sum += doMath(value); });
for in
let sum = 0; for(const index in arr) { sum += doMath(arr[index]); }
for
let sum = 0; for(var i = 0; i < arr.length; i++) { const value = arr[i]; sum += doMath(value); }
for of
let sum = 0; for(const value of arr) { sum += doMath(value); }
lodash foreach
let sum = 0; _.forEach(arr, (value) => { sum += doMath(value); });
for reverse
let sum = 0; for(var i = arr.length - 1; i >= 0; i--) { const value = arr[i]; sum += doMath(value); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
for in
for
for of
lodash foreach
for reverse

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what each test case is comparing, along with their pros and cons.

**Benchmark Definition JSON**

The benchmark defines six different approaches to iterate over an array:

1. `for` loop
2. `forEach` method
3. `for...in` loop
4. `for...of` loop
5. Lodash's `forEach` function (`_.forEach`)
6. A reversed `for` loop

**Individual Test Cases**

Here's a brief explanation of each test case:

1. **`forEach`**: Iterates over the array using the `forEach` method, which calls a callback function for each element in the array.
	* Pros: Easy to use, concise syntax.
	* Cons: May have performance issues due to the creation of a new scope and closure for each iteration.
2. **`for...in`**: Iterates over the array using a traditional `for` loop with an `in` statement, which iterates over the array's indices.
	* Pros: Can be faster than `forEach`, as it avoids creating a new scope and closure for each iteration.
	* Cons: May not work well with non-enumerable properties, and can lead to slower performance due to the use of `in`.
3. **`for` loop**: Iterates over the array using a traditional `for` loop with an index variable.
	* Pros: Fast and efficient, as it avoids creating a new scope and closure for each iteration.
	* Cons: May require more code than other approaches, and can be less readable due to the use of multiple variables.
4. **`for...of`**: Iterates over the array using a modern `for...of` loop, which is similar to a `forEach` loop but uses an iterator expression instead of a callback function.
	* Pros: Concise syntax, easy to read and maintain.
	* Cons: May not be supported in older browsers or environments.
5. **Lodash's `forEach`**: Iterates over the array using Lodash's `forEach` function, which is similar to the built-in `forEach` method but provides additional functionality and options.
	* Pros: Provides more flexibility and control than the built-in `forEach` method, especially when used with other Lodash functions.
	* Cons: May add unnecessary overhead due to the use of a separate library.
6. **Reversed `for` loop**: Iterates over the array in reverse order using a traditional `for` loop with an index variable that decrements on each iteration.
	* Pros: Can be faster than other approaches, especially for large arrays, since it avoids creating a new scope and closure for each iteration.
	* Cons: May require more code than other approaches, and can be less readable due to the use of multiple variables.

**Library Used**

Lodash is used in two test cases: `lodash foreach` and `_.forEach`. Lodash is a popular JavaScript library that provides a wide range of functions for working with arrays, objects, and other data structures. The `forEach` function provided by Lodash is similar to the built-in `forEach` method but offers additional functionality and options.

**Special JS Feature or Syntax**

None of the test cases use any special JavaScript features or syntax that would require a deep understanding of the language. However, it's worth noting that the `for...of` loop, which is used in two test cases, is a modern feature that was introduced in ECMAScript 2015 (ES6). It provides a concise and expressive way to iterate over arrays and other iterable objects.

**Other Alternatives**

If you're looking for alternative approaches to iterating over an array, here are a few options:

1. **`map()` method**: Instead of using a loop or a `forEach` function, you can use the `map()` method to create a new array with transformed values.
2. **`reduce()` method**: The `reduce()` method is similar to `map()`, but it accumulates a value across each iteration instead of creating a new array.
3. **Generators**: Generators are a type of function that can be used to iterate over arrays or other iterable objects in a more expressive way than traditional loops.
4. **Iterators**: Iterators are objects that provide a way to traverse an iterable object, such as an array or a set.

These alternatives may offer different trade-offs and performance characteristics depending on your specific use case, so be sure to evaluate them carefully before choosing an approach.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.122 Safari/537.36

Browser/OS: Chrome 80 on Linux

View result in a separate tab

Test name	Executions per second
forEach	367.4 Ops/sec
for in	300.7 Ops/sec
for	259.4 Ops/sec
for of	426.3 Ops/sec
lodash foreach	378.8 Ops/sec
for reverse	328.3 Ops/sec

Related benchmarks:

for vs forEach vs for in vs for of vs lodash vs for reverse (2) (version: 0)

for vs forEach vs for in vs for of vs lodash vs for reverse

Comparing performance of: forEach vs for in vs for vs for of vs lodash foreach vs for reverse

Created: 4 years ago by: Guest

Jump to the latest result

forEach

for in

for

for of

lodash foreach

for reverse

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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