Benchmark: Array.from vs. Spread

Script Preparation code:

var fooSet = new Set();
for(var i=0;i<1000;i++) {
  fooSet.add(i);
}

Tests:

Array.from
var other = Array.from(fooSet);
Spread
var other = [...fooSet];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.from
Spread

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):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**

The benchmark is comparing two approaches for creating an array from a set: `Array.from()` and the spread operator (`...`). The script preparation code initializes an empty set `fooSet` with 1000 elements, which is then used to create the array.

**Options being compared**

* **`Array.from(fooSet)`**: This method creates a new array by copying all elements from the specified iterable (`fooSet`) into a new array. The original `fooSet` remains unchanged.
	+ Pros:
		- More explicit and readable way of creating an array from an iterable.
		- Can be used with any iterable, not just sets or arrays.
	+ Cons:
		- Creates a new object that can lead to memory allocation overhead for large datasets.
* **`[...fooSet]` (spread operator)**: This method creates a new array by spreading the elements of the specified iterable (`fooSet`) into a new array.
	+ Pros:
		- More concise and expressive way of creating an array from an iterable.
		- Often faster than `Array.from()` because it avoids the overhead of creating a new object and copying all elements.
* **Other considerations**:
	+ The benchmark only compares these two specific approaches, so other methods like `slice()` or `map()` are not being tested.

**Library and purpose**

In this benchmark, no external libraries are used beyond the built-in JavaScript features. The only library-like concept is the iterable (`fooSet`) itself, which is a data structure that can be iterated over.

**Special JS feature or syntax**

The spread operator (`[...fooSet]`) was introduced in ECMAScript 2015 (ES6) and allows for more concise array creation from iterables. It's a modern feature that's becoming increasingly common in JavaScript codebases.

**Benchmark result interpretation**

According to the latest benchmark results, the spread operator (`[...fooSet]`) is slightly faster than `Array.from(fooSet)` on this specific test case. However, it's essential to note that this may not be representative of all scenarios or use cases, as the underlying implementation and optimizations can vary between browsers and environments.

**Alternatives**

Other alternatives for creating an array from an iterable include:

* `slice()`: Creates a new array by slicing the elements of an existing array.
* `map()`: Applies a transformation function to each element of an iterable and returns a new array with the results.
* Other libraries or frameworks may provide additional methods or APIs for creating arrays from iterables.

Keep in mind that these alternatives might not be as efficient or concise as the spread operator or `Array.from()` in certain cases, but they can offer more control or flexibility in specific use scenarios.

Related benchmarks:

Array.from vs. Spread (version: 0)

Comparing performance of: Array.from vs Spread

Created: 2 years ago by: Guest

Jump to the latest result

Array.from

Spread

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):