Benchmark: Get array from iterable with Array.from() vs for loop

Tests:

Array.from()
var iterable = document.all,a = Array.from(iterable)
for loop
for(var iterable=document.all,a=Array(iterable.length),iterator=iterable[Symbol.iterator](),i=0,next;!(next=iterator.next()).done;)a[i++]=next.value;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.from()
for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) FxiOS/116.4 Mobile/15E148 Safari/605.1.15

Browser/OS: Mobile Safari 16 on iOS 16.6

View result in a separate tab

Test name	Executions per second
Array.from()	1798466.2 Ops/sec
for loop	1633965.4 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark.

**Benchmark Definition:**

The benchmark compares two approaches for creating an array from an iterable:

1. `Array.from()`
2. For loop (using the iterator protocol)

**What is being tested?**

In this case, we're testing which approach is faster and more efficient in terms of execution speed on a specific JavaScript engine.

**Options compared:**

* `Array.from()` vs for loop

**Pros and Cons:**

1. `Array.from()`: This method is often considered convenient and easy to read, as it uses the spread operator (`...`) to create an array from an iterable. However, performance-wise, this approach can be slower than a traditional for loop.
2. For loop (iterator protocol): This approach is generally faster and more efficient because it allows the engine to optimize the iteration process using the iterator protocol.

**Other considerations:**

* Performance: The goal of this benchmark is to determine which approach yields better performance on the specified JavaScript engine.
* Code readability and maintainability: While `Array.from()` might be more concise, a for loop can provide better insight into the underlying iteration mechanism.
* Platform dependence: The results may vary depending on the platform (e.g., browser, Node.js) and JavaScript engine.

**Library and syntax considerations:**

The benchmark uses the `document.all` property to create an iterable from the DOM. This suggests that the test is running in a web environment.

No special JavaScript features or syntax are being used in this benchmark.

**Alternatives:**

If you're interested in exploring alternative approaches, here are a few options:

* Using other array creation methods like `Array.from()` with a custom function to create an iterable (e.g., using `map()`, `reduce()`, or `slice()`) versus a for loop.
* Comparing performance with different browsers or JavaScript engines (e.g., Chrome, Firefox, Node.js).
* Adding more test cases that cover different scenarios, such as:
	+ Creating arrays from objects or other data structures.
	+ Handling large datasets or edge cases.

Keep in mind that these alternatives may require significant modifications to the benchmark code.

Related benchmarks:

Get array from iterable with Array.from() vs for loop (version: 0)

Array.from is notoriously slow. This compares creating an Array from an iterable with Array.from() vs a for loop.

Comparing performance of: Array.from() vs for loop

Created: one year ago by: Guest

Jump to the latest result

Array.from()

for loop

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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