Benchmark: for vs enumerated forEach

Script Preparation code:

var arr = [];
for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}

Tests:

for
var clone = []; for (var i = 0; i < arr.length; i++) { clone[i] = arr[i]; }
forEach
var clone = []; arr.forEach((element) => { clone.push(element); });
forEach (enumerated)
var clone = []; arr.forEach((element, i) => { clone[i] = element; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
forEach
forEach (enumerated)

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 benchmark and explore what's being tested.

**Benchmark Overview**

The benchmark is designed to compare the performance of three approaches for cloning an array in JavaScript:

1. Using a traditional `for` loop
2. Using the `forEach` method with and without specifying the index parameter

**Options Being Compared**

* **Traditional `for` loop**: This approach uses a traditional `for` loop to iterate over the elements of the original array, creating a new clone.
* **`forEach` method with no index parameter**: This approach uses the `forEach` method to iterate over the elements of the original array, but doesn't specify an index parameter. Instead, it uses the default indexing mechanism, where each element is assigned to its own property on the clone object.
* **`forEach` method with index parameter**: This approach uses the `forEach` method to iterate over the elements of the original array, specifying both the element and index parameters. It then assigns the element to a specific property on the clone object.

**Pros and Cons**

* **Traditional `for` loop**:
	+ Pros: straightforward, easy to understand
	+ Cons: can be slower due to the overhead of creating a new variable `i`
* **`forEach` method with no index parameter**:
	+ Pros: concise, doesn't require manual indexing
	+ Cons: may have performance issues due to the default indexing mechanism
* **`forEach` method with index parameter**:
	+ Pros: provides better control over the cloning process, can be faster than the other two approaches
	+ Cons: requires more code to specify both element and index parameters

**Library Used**

In this benchmark, no specific library is used beyond the built-in `Array.prototype.forEach()` method.

**Special JS Features/Syntax**

The benchmark uses the `forEach` method, which is a modern JavaScript feature introduced in ECMAScript 5. It's widely supported across modern browsers and engines.

**Other Considerations**

* The benchmark measures the execution time per second for each test case.
* The results are reported as an array of objects, where each object contains metadata about the test run (e.g., browser, device platform, operating system, etc.).
* The benchmark provides a raw UA string that can be used to identify the specific browser and version being tested.

**Alternatives**

If you're interested in exploring alternative approaches for cloning arrays in JavaScript, consider:

* Using `Array.prototype.map()` or `Array.prototype.slice()` methods.
* Implementing your own custom cloning function using recursion or iteration.
* Using a library like Lodash, which provides an efficient and concise way to clone arrays.

Keep in mind that the choice of approach depends on the specific use case and performance requirements.

Related benchmarks:

for vs enumerated forEach (version: 0)

Comparing performance of: for vs forEach vs forEach (enumerated)

Created: 5 years ago by: Guest

Jump to the latest result

for

forEach

forEach (enumerated)

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):