Benchmark: Iterable toArray(): push() vs spread

Script Preparation code:

var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
var iter = arr.values();

Tests:

push()
var result1 = []; for (const val of iter) { result1.push(val); }
spread
var result2 = [...iter];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
push()
spread

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.93 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
push()	5310464.5 Ops/sec
spread	3426611.5 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 and explain what's being tested.

**What is being tested?**

The benchmark measures the performance difference between two approaches to convert an iterable array to an array using JavaScript:

1. Using `Array.prototype.push()`: This approach iterates over the iterable array, pushing each value into a new empty array.
2. Using the spread operator (`...`): This approach creates a new array by spreading the values of the iterable array.

**Options compared**

Two options are being compared: `push()` and the spread operator (`...`). Both approaches have their pros and cons:

**Push()**

Pros:

* Easy to implement and understand.
* Works well with small arrays or when you need to add a single value at a time.
* Can be optimized for small arrays by using `Array.prototype.splice()` instead of `push()`.

Cons:

* Requires multiple iterations over the array, which can lead to slower performance for large datasets.
* Inefficient use of memory as it creates a new array with each push operation.

**Spread operator (`...`)**

Pros:

* More concise and expressive than using `Array.prototype.push()`.
* Creates a new array in a single operation, reducing overhead.
* Can be optimized by using `Array.prototype.slice()` or other array methods to create the new array.

Cons:

* Requires modern JavaScript features (ECMAScript 2018+).
* May not work as expected with older browsers or environments that don't support the spread operator.

**Library and purpose**

None of the test cases uses a specific library, but they do use `Array.prototype.values()` to create an iterable array from a regular array. The `values()` method is part of the JavaScript standard library and provides an iterable sequence of values from the original array.

**Special JS feature or syntax**

The benchmark assumes that the JavaScript engine being tested supports modern features such as iterable arrays, the spread operator (`...`), and the `Array.prototype.values()` method.

**Other alternatives**

For this specific problem, there aren't many alternative approaches. However, if you need to convert an array to a different data structure (e.g., from array to object), some other options might include:

* Using `Object.assign()` or `reduce()`
* Using `Array.prototype.map()` with the identity function
* Using a library like Lodash's `mapValues()` method

Keep in mind that each approach has its own trade-offs and may be more suitable for specific use cases.

I hope this explanation helps!

Related benchmarks:

Iterable toArray(): push() vs spread (version: 0)

Comparing performance of: push() vs spread

Created: 3 years ago by: Guest

Jump to the latest result

push()

spread

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):