Benchmark: Array.from vs forEach index

Tests:

Array.from
var fooSet = new Set(); for(var i=0;i<100;i++) { fooSet.add(i); } var other = Array.from(fooSet.values());
forEach
var fooSet = new Set(); for(var i=0;i<100;i++) { fooSet.add(i); } let index = 0; fooSet.forEach(value => index++);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.from
forEach

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark in detail.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark, where users can compare the performance of two approaches: `Array.from` and `forEach` when used with indexing.

**Options Compared**

Two options are compared:

1. **`Array.from`**: This method creates a new array from an iterable (in this case, a `Set`) and returns an empty array.
2. **`forEach`**: This method executes a provided callback function once for each element in the iterable.

**Pros and Cons of Each Approach**

* **`Array.from`**:
	+ Pros: It is generally faster than using `forEach` with indexing because it avoids the overhead of executing a callback function for each element.
	+ Cons: It creates an additional array, which can consume memory. Additionally, if you need to access elements by their index, you'll still have to iterate through the array.
* **`forEach`**:
	+ Pros: It is more flexible than `Array.from`, as it allows you to execute a callback function that may perform some operation on each element without creating an additional data structure.
	+ Cons: It can be slower than using `Array.from` because of the overhead of executing the callback function for each element.

**Library and Syntax**

In this benchmark, both options use a `Set`, which is a built-in JavaScript data structure that stores unique values. The `Set` object is used to create an iterable that can be converted to an array using `Array.from`.

There are no special JavaScript features or syntaxes used in this benchmark.

**Other Considerations**

When choosing between these two approaches, consider the specific requirements of your use case:

* Do you need to access elements by their index? If so, `Array.from` might be a better choice.
* Are you performing some operation on each element that can't be done without creating an additional data structure? If so, `forEach` might be a better choice.

**Alternative Approaches**

Other approaches to convert an iterable to an array or perform operations on each element include:

1. **Using the spread operator (`...`)**: For example, `[...fooSet.values()]`.
2. **Using the `map()` method**: For example, `Array.from(fooSet.values()).map(value => value)`.
3. **Using a traditional loop**: For example, `var arr = []; for (let i = 0; i < fooSet.size; i++) { arr.push(fooSet.values()[i]); }`.

Each of these approaches has its own trade-offs in terms of performance and memory usage.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36

Browser/OS: Chrome 90 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Array.from	338642.1 Ops/sec
forEach	283380.2 Ops/sec

Related benchmarks:

Array.from vs forEach index (version: 0)

Comparing performance of: Array.from vs forEach

Created: 3 years ago by: Guest

Jump to the latest result

Array.from

forEach

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):