Benchmark: Array creation 234234

Tests:

First
[].concat(Array.from({ length: 1000 }, (_, idx) => idx))
Second
[...Array(1000).keys()]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
First
Second

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/88.0.4324.104 Safari/537.36

Browser/OS: Chrome 88 on Windows

View result in a separate tab

Test name	Executions per second
First	12320.8 Ops/sec
Second	31618.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net!

**What is tested?**

The provided benchmark measures the performance of two different ways to create an array of numbers in JavaScript. The test case compares the execution time of:

1. Using `Array.from()` and concatenating it with `[ ]`.
2. Using destructuring assignment (`[...Array(1000).keys()]`).

**Options compared:**

The benchmark is comparing the performance of two different approaches to create an array of numbers:

1. **Using `Array.from()` and concatenation**: This approach creates a new array by iterating over a range of values using `Array.from()`. The resulting array is then concatenated with an empty array (`[ ]`) using the spread operator (`...`).
2. **Destructuring assignment**: This approach uses destructuring assignment to extract key-value pairs from the object `{ length: 1000, keys: () => Array(1000).keys() }`, and then assigns the result to a new variable (`[...Array(1000).keys()]`).

**Pros and Cons of each approach:**

1. **Using `Array.from()` and concatenation**:
	* Pros:
		+ Easy to understand and implement.
		+ Can be useful for creating arrays with specific properties (e.g., length, keys).
	* Cons:
		+ Creates a new array with the same elements as the original array, which can lead to unnecessary memory allocations.
		+ May not be suitable for large datasets due to performance overhead.
2. **Destructuring assignment**:
	* Pros:
		+ More concise and expressive than concatenation.
		+ Can avoid creating a new array altogether by reusing the existing object's keys property.
	* Cons:
		+ Less intuitive for non-JavaScript developers (e.g., those familiar with imperative programming).
		+ May not be supported in older browsers or JavaScript engines.

**Special JS feature or syntax:**

The benchmark uses the spread operator (`...`) and destructuring assignment, which are modern JavaScript features. These features were introduced in ECMAScript 2015 (ES6) and have since become widely adopted in modern JavaScript development.

**Other considerations:**

* The benchmark is running on a desktop browser (Chrome 88) with a Windows operating system.
* The `ExecutionsPerSecond` value indicates the number of times the test case was executed per second, which provides an idea of performance.

**Alternatives:**

If you're interested in exploring alternative approaches to creating arrays in JavaScript, here are some options:

1. **Using `Array.prototype.slice()`**: This approach creates a shallow copy of the original array using slicing.
2. **Using `Array.from()` with a generator**: This approach uses a generator function to create an iterator that yields numbers from 0 to 999.
3. **Using native WebAssembly (WASM)**: This approach uses WASM to compile JavaScript code into machine code, which can provide significant performance improvements for large-scale computations.

I hope this explanation helps you understand the benchmark and its test cases!

Related benchmarks:

Array creation 234234 (version: 0)

Comparing performance of: First vs Second

Created: 3 years ago by: Guest

Jump to the latest result

First

Second

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):