Benchmark: Fill array with random integers

Tests:

Set-length array
let arr = Array(1000).fill(undefined).map(e => Math.floor(Math.random()*1000000+1));
Array.push
let arr = []; for (i=0; i<1000001; i++){arr.push(Math.floor(Math.random()*1000000+1))}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Set-length array
Array.push

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36

Browser/OS: Chrome 69 on Windows

View result in a separate tab

Test name	Executions per second
Set-length array	836.4 Ops/sec
Array.push	1.1 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 MeasureThat.net and explore what's being tested in this benchmark.

**Benchmark Definition**

The benchmark definition is a JSON object that provides metadata about the test case. In this case, there are two benchmark definitions:

1. `Fill array with random integers`: This benchmark definition describes the test scenario, where an array of 1000 elements is filled with random integers between 1 and 999,999 (inclusive).
2. Script Preparation Code: The script preparation code is empty (`null`), which means that no specific code needs to be executed before running the test.
3. HTML Preparation Code: The HTML preparation code is also empty (`null`), indicating that no special HTML setup is required.

**Individual Test Cases**

There are two individual test cases:

1. `Set-length array`: This test case uses a concise syntax to create an array of 1000 elements using `Array(1000).fill(undefined).map(e => Math.floor(Math.random()*1000000+1))`.
2. `Array.push`: This test case uses a traditional `for` loop to push 1000 random integers onto an empty array (`let arr = [];\r\nfor (i=0; i<1000001; i++){arr.push(Math.floor(Math.random()*1000000+1))}`).

**Library and Purpose**

Neither of the test cases uses any external libraries. The `Array` constructor is a built-in JavaScript function, and the `Math.random()` function is also a built-in function.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax being used in either test case.

**Pros and Cons of Different Approaches**

1. **Set-length array**:
	* Pros: Concise and efficient way to create an array.
	* Cons: May not be as intuitive for developers who are unfamiliar with the `fill()` method.
2. **Array.push**:
	* Pros: Traditional and well-understood approach that many developers will be familiar with.
	* Cons: Less concise and potentially less efficient than the set-length array approach.

**Other Alternatives**

If you were to create a similar benchmark, other alternatives for the `set-length array` approach could include:

* Using `Array.from()`: `Array.from(new Array(1000), () => Math.floor(Math.random()*1000000+1))`
* Using a library like Lodash's `repeat()` function: `_._.repeat(1000)(Math.floor(Math.random()*1000000+1))`

For the `Array.push` approach, alternative methods could include:

* Using `splice()`: `let arr = []; for (i=0; i<1000001; i++){arr.splice(i, 0, Math.floor(Math.random()*1000000+1))}`
* Using a library like Lodash's `repeat()` function with the `push()` method: `_._.forEach(1000)(arr.push, Math.floor(Math.random()*1000000+1))`

Keep in mind that these alternatives may not necessarily change the outcome of the benchmark, but they could provide additional insights into different aspects of JavaScript performance.

Related benchmarks:

Fill array with random integers (version: 0)

Fill Array(1000) with random 1 - 999999 inclusive

Comparing performance of: Set-length array vs Array.push

Created: 6 years ago by: Guest

Jump to the latest result

Set-length array

Array.push

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):