Benchmark: array from - MeasureThat.net

Tests:

Array.from({...})
Array.from({ length: 1000 }, () => 0)
Array.from(Array())
Array.from(Array(1000), () => 0)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.from({...})
Array.from(Array())

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_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) FxiOS/137.0 Mobile/15E148 Safari/605.1.15

Browser/OS: Mobile Safari 16 on iOS 16.2

View result in a separate tab

Test name	Executions per second
Array.from({...})	82863.7 Ops/sec
Array.from(Array())	52804.5 Ops/sec

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 and explain what's being tested.

The test case uses the `Array.from()` method, which is a JavaScript array creation method that creates a new array from an iterable (such as an array or string) by mapping each element to a new value. The purpose of this method is to provide a concise way to create arrays with a specific number of elements.

In this benchmark, there are two test cases:

1. `Array.from(Array(1000), () => 0)`:
This test case creates an array of 1000 elements using the `Array` constructor and then passes it as an argument to `Array.from()`. The callback function `(x) => 0` is used to map each element to a new value, which is always 0. This test case measures how fast `Array.from()` can create an array from a pre-existing array.

2. `Array.from({ length: 1000 }, () => 0)`:
This test case creates an object with a specific number of properties (1000) using the `{ length: 1000 }` syntax, and then passes it as an argument to `Array.from()`. The callback function `(x) => 0` is used to map each property to a new value. This test case measures how fast `Array.from()` can create an array from an object.

Now, let's discuss the options being compared:

**Option 1: Pre-existing Array**

Using a pre-existing array as input for `Array.from()`. This approach has pros and cons:

Pros:

* Fast creation of an array
* Easy to generate arrays with specific sizes

Cons:

* Requires extra memory allocation (to store the original array)
* May not be as efficient if the original array is large

**Option 2: Object with Specific Properties**

Using an object with a specific number of properties as input for `Array.from()`. This approach has pros and cons:

Pros:

* Does not require extra memory allocation
* Can be more efficient than using pre-existing arrays, especially for large inputs

Cons:

* Requires a deeper understanding of objects and their syntax
* May not be as straightforward to generate arrays with specific sizes

Other considerations:

* Performance: Both options have similar performance characteristics, but the object-based approach might be slightly faster due to reduced memory allocation.
* Memory usage: The pre-existing array approach requires more memory allocation than the object-based approach.

Regarding the libraries used in this benchmark, none are explicitly mentioned. However, it's worth noting that `Array.from()` is a built-in JavaScript method and does not rely on any external libraries.

As for special JavaScript features or syntax, this benchmark uses a few:

* The `{ length: 1000 }` syntax to create an object with specific properties.
* The callback function `(x) => 0` used in both test cases.

If you're interested in exploring alternative approaches or testing other scenarios, here are some suggestions:

* Use different array creation methods (e.g., `Array.from()`, `Array.prototype.fill()`, `Array.from(0)`).
* Test with varying input sizes to see how performance changes.
* Experiment with different object syntaxes (e.g., `{ prop1: 1, prop2: 2 }`) and see if they affect performance.

Keep in mind that these alternatives might not be directly related to the specific questions being asked by this benchmark.

Related benchmarks:

array from (version: 0)

Comparing performance of: Array.from({...}) vs Array.from(Array())

Created: 3 years ago by: Guest

Jump to the latest result

Array.from({...})

Array.from(Array())

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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