Benchmark: forEach, for, 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); })
map
arr.map(item => someFn(item))
for
var len = arr.length; for (var i = 0; i < len; i++) { someFn(arr[i]); }
for 2
var len = arr.length; for (var i = len -1 ; i >= 0; i--) { someFn(arr[i]); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
map
for
for 2

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a JavaScript microbenchmark that tests the performance of three different approaches: `forEach`, `map`, and `for`. The benchmark is designed to measure how quickly these approaches can execute a function on an array of numbers.

**Script Preparation Code**

The script preparation code creates an empty array `arr` with 1000 elements, each initialized with its index. It also defines a function `someFn(i)` that takes an integer `i` as input and returns the result of multiplying `i` by 3 and 8.

**Html Preparation Code**

There is no HTML preparation code provided in this benchmark.

**Individual Test Cases**

The benchmark consists of four test cases:

1. **forEach**: Tests the performance of using a `forEach` loop to execute `someFn` on each element of the array.
2. **map**: Tests the performance of using the `map()` method to transform the elements of the array into new values by applying `someFn`.
3. **for**: Tests the performance of using a traditional `for` loop to iterate over the elements of the array and execute `someFn`.
4. **for 2**: Tests the performance of using a traditional `for` loop with an index variable that starts from the end of the array and decrements until it reaches 0, executing `someFn`.

**Library Usage**

There is no explicit library usage in this benchmark.

**Special JS Features or Syntax**

The benchmark uses the following special features:

* The arrow function syntax (`=>`) is used in the `map()` method test case.
* The traditional `for` loop with an index variable that starts from the end of the array and decrements until it reaches 0 is used in the `for 2` test case.

**Pros and Cons of Different Approaches**

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

* **forEach**: Easy to read and write, but can be slower due to the overhead of the loop.
	+ Pros: Simple and intuitive syntax.
	+ Cons: Can be slower than other approaches.
* **map**: More concise and efficient than `forEach`, but may require more browser support.
	+ Pros: Faster execution time and more concise syntax.
	+ Cons: May not work in older browsers.
* **for**: Traditional loop syntax, which can be faster than `forEach` and `map`, but is also more verbose.
	+ Pros: Fast execution time and more control over the loop iteration.
	+ Cons: More difficult to read and write.

**Other Considerations**

When choosing between these approaches, consider the following factors:

* **Readability**: How easy is the code to understand?
* **Maintainability**: How easy is it to modify or extend the code?
* **Performance**: How fast does the code execute?
* **Browser Support**: Are older browsers supported?

**Alternatives**

Other alternatives for this benchmark could be:

* Using a different array size or data distribution
* Introducing additional complexity, such as nested loops or conditional statements
* Using a different programming paradigm, such as recursion or async/await
* Comparing the performance of other JavaScript engines or versions

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Browser/OS: Chrome 68 on Mac OS X 10.13.6

View result in a separate tab

Test name	Executions per second
forEach	12494.0 Ops/sec
map	12117.8 Ops/sec
for	6562.2 Ops/sec
for 2	6404.7 Ops/sec

Related benchmarks:

forEach, for, map (version: 0)

Comparing performance of: forEach vs map vs for vs for 2

Created: 6 years ago by: Registered User

Jump to the latest result

forEach

map

for

for 2

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):