Benchmark: foreach vs some vs for..of vs for with length vs map

Script Preparation code:

var array = new Array(1000);

Tests:

foreach
array.forEach(function(i) { array[i]; });
some
array.some(function(i) { array[i]; });
for..of
for (var i of array) { array[i]; }
for with length
var length = array.length; for (var i = 0; i < length; i++) { array[i]; }
map
array.map(function(i) { array[i]; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
some
for..of
for with length
map

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 benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Description:**
The benchmark is designed to compare the performance of different loop constructs in JavaScript:

1. `forEach`
2. `some`
3. `for..of`
4. `for` with manual length check
5. `map`

**Purpose:**
The purpose of this benchmark is to determine which loop construct is most efficient and suitable for a given use case.

**Options Compared:**

1. **`forEach`**: The `forEach` method executes the provided callback function for each element in the array, without modifying the original array.
	* Pros:
		+ Easy to read and write
		+ Does not modify the original array
	* Cons:
		+ May be slower due to the overhead of calling a function on each iteration
2. **`some`**: The `some` method returns `true` as soon as the callback function returns `true` for at least one element in the array.
	* Pros:
		+ Can be faster than `forEach` since it stops iterating as soon as the condition is met
	* Cons:
		+ May not be suitable for use cases where all elements need to be processed
3. **`for..of`**: The `for..of` loop iterates over the array using an iterator, which returns the values of each element.
	* Pros:
		+ Can be more efficient than traditional loops since it uses a built-in iterator
		+ Easy to read and write
4. **`for` with length check**: The manual `for` loop checks the length of the array before iterating over it.
	* Pros:
		+ Can be faster than other options if the number of iterations is known beforehand
5. **`map`**: The `map` method creates a new array by applying the provided callback function to each element in the original array.
	* Pros:
		+ Returns a new array with transformed values, making it suitable for use cases where you need a new array
	* Cons:
		+ Creates a new array, which can be memory-intensive

**Library Used:**
None.

**Special JS Features/Syntax:**
The benchmark uses the `for..of` loop, which is a relatively recent feature introduced in ECMAScript 2015 (ES6). This loop construct allows for more concise and expressive iteration over arrays and other iterable objects. The `some` method also returns a boolean value, which can be useful in certain use cases.

**Other Considerations:**

* The benchmark uses Chrome 103 as the browser, so results may not be applicable to other browsers.
* The test environment is set to run on a desktop platform (Windows), which might affect performance compared to running on mobile devices or other platforms.
* The number of elements in the array (1000) is relatively small, which might not accurately represent the performance of larger arrays.

**Alternatives:**
Other loop constructs that could be included in this benchmark are:

* `while` loops
* Recursive functions
* `reduce()` method

However, these alternatives might not provide a fair comparison to the listed options, as they may have different use cases or performance characteristics.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.5060.114 Safari/537.36 Edg/103.0.1264.62

Browser/OS: Chrome 103 on Windows

View result in a separate tab

Test name	Executions per second
foreach	444825.5 Ops/sec
some	494053.6 Ops/sec
for..of	6748.2 Ops/sec
for with length	8534.9 Ops/sec
map	287142.0 Ops/sec

Related benchmarks:

foreach vs some vs for..of vs for with length vs map (version: 0)

Compare loop performance

Comparing performance of: foreach vs some vs for..of vs for with length vs map

Created: 4 years ago by: Guest

Jump to the latest result

foreach

some

for..of

for with length

map

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):