Benchmark: Array loop vs foreach vs map - maks test

Script Preparation code:

   var arr = [];
    for (var i = 0; i < 999999; i++) {
      arr[i] = i;
    }
  
    function someFn(i) {
      return i * 3 * 8;
    }

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for
map

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

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

1. `Array.forEach()`
2. Manual loop using a `for` loop
3. Array method `map()`

In the provided JSON, we have three test cases: `foreach`, `for`, and `map`. Each test case has a corresponding benchmark definition in the format of `arr.[iteration method](function (item) { return someFn(item); })`.

**Options Compared**

The benchmark compares the performance of three different iteration methods:

1. **`Array.forEach()`**: This method iterates over an array using a callback function, which is executed for each element in the array.
2. **Manual loop using `for` loop**: This approach uses a traditional `for` loop to iterate over the array, where the index `i` is incremented on each iteration.
3. **Array method `map()`**: This method creates a new array with the results of applying the provided function to each element in the original array.

**Pros and Cons**

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

* **`Array.forEach()`**:
	+ Pros: concise, easy to read, and maintainable code; automatic index iteration.
	+ Cons: might be slower due to overhead of callback function execution.
* **Manual loop using `for` loop**:
	+ Pros: fine-grained control over iteration, potential for better performance in some cases.
	+ Cons: more verbose, error-prone, and less readable code; manual index management can lead to off-by-one errors.
* **Array method `map()`**:
	+ Pros: concise and expressive, creates a new array with the transformed elements.
	+ Cons: creates a new array, potentially consumes more memory; might be slower due to overhead of function execution.

**Libraries Used**

None in this specific benchmark. The test code only uses standard JavaScript features and libraries (e.g., `Array`).

**Special JS Features/Syntax**

There are no special JavaScript features or syntaxes used in this benchmark, other than the `let` keyword for declaring variables (which is a modern JavaScript feature introduced in ECMAScript 2015).

**Other Alternatives**

If you're interested in exploring alternative iteration methods, here are some additional approaches:

* **`Array.reduce()`**: This method reduces an array to a single value by applying a function to each element.
* **`Array.some()`** or **`Array.every()`**: These methods test whether at least one (or all) elements in the array pass a provided condition.

These alternative iteration methods can be useful in specific scenarios, but might not be as commonly used as `forEach`, `for`, and `map`.

I hope this explanation helps you understand the benchmark and its approaches!

Related benchmarks:

Array loop vs foreach vs map - maks test (version: 0)

Comparing performance of: foreach vs for vs map

Created: 5 years ago by: Guest

Jump to the latest result

foreach

for

map

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):