Benchmark: compare the ways to generate a random array for iteration

compare the ways to generate a random array for iteration (version: 0)

- Array.apply: Array.apply(null, Array(100)) - Destructuring operator: [...Array(100)] - Array.prototype.fill Array(100).fill(undefined) - Array.from Array.from({ length: 100 })

Comparing performance of: Array.apply(null, Array(n)) vs [...Array(n)] vs Array(n).fill(null) vs Array.from({ length: n }) vs Array.from({ length:n }, (item, i) => i)

Created: 9 months ago by: Guest

Jump to the latest result

Tests:

Array.apply(null, Array(n))
Array.apply(null, Array(1000)).map(() => Math.random());
[...Array(n)]
[...Array(1000)].map(() => Math.random());
Array(n).fill(null)
Array(1000).fill(null).map(() => Math.random());
Array.from({ length: n })
Array.from({ length: 1000 }).map(() => Math.random());
Array.from({ length:n }, (item, i) => i)
Array.from({ length:1000 }, () => Math.random());

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.apply(null, Array(n))
[...Array(n)]
Array(n).fill(null)
Array.from({ length: n })
Array.from({ length:n }, (item, i) => i)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**Benchmark Definition:**

The provided JSON represents a benchmarking test case created on MeasureThat.net. The purpose of this benchmark is to compare different ways of generating a random array for iteration. The test includes four approaches:

1.  **Array.apply**: This method uses `Array.apply(null, Array(100))` to create an array and then maps over it using the callback function.
2.  **Destructuring operator**: This approach uses the spread operator (`...`) to create an array from `Array(100)`.
3.  **Array.prototype.fill**: This method creates an array of a specified length (in this case, 1000) and fills it with `null`, then maps over the resulting array.
4.  **Array.from**: This method is used to create an array from an object with a specified length.

**Options Compared:**

The benchmark compares these four approaches:

*   Array.apply
*   Destructuring operator
*   Array.prototype.fill
*   Array.from

Each approach has its own strengths and weaknesses, which we'll discuss below.

**Pros and Cons of Each Approach:**

1.  **Array.apply**: This method is generally considered old-fashioned and not recommended for new code. However, it can be useful in certain situations where you need to support older browsers or environments that don't support modern JavaScript features.
    *   Pros:
        *   Works across a wide range of browsers and environments
    *   Cons:
        *   Not recommended for new code due to its outdated nature
2.  **Destructuring operator**: This approach is concise and easy to read, making it a popular choice among modern JavaScript developers.
    *   Pros:
        *   Concise and readable syntax
        *   Works well with most modern browsers and environments
    *   Cons:
        *   May not work in older browsers or environments that don't support the spread operator
3.  **Array.prototype.fill**: This method is useful when you need to fill an array with a specific value, but it's not ideal for iterating over the array.
    *   Pros:
        *   Fast and efficient for filling arrays with values
    *   Cons:
        *   Not suitable for iteration due to its implementation
4.  **Array.from**: This method is a modern addition to the JavaScript language and provides an elegant way to create arrays from objects.
    *   Pros:
        *   Concise and readable syntax
        *   Works well with most modern browsers and environments
    *   Cons:
        *   May not work in older browsers or environments that don't support the spread operator

**Library Usage:**

There is no explicit library usage mentioned in the benchmark definition. However, some methods like `Array.prototype.fill` might use internal browser libraries to implement their behavior.

**Special JS Features/Syntax:**

The benchmark uses several modern JavaScript features:

*   Destructuring operator (`...`)
*   Spread syntax (`Array.from({ length: n })`)

These features are widely supported across most modern browsers and environments, but it's essential to ensure compatibility when using them in production code.

**Alternatives:**

If you're looking for alternative ways to generate random arrays for iteration, you might consider the following approaches:

*   **Random number generator**: You can use a high-quality random number generator library like `crypto` or `randomseed` to generate random numbers.
*   **Array.from with a custom mapping function**: Instead of using an array comprehension, you can use `Array.from` with a custom mapping function to create the array.

However, keep in mind that these alternatives might not be as efficient or readable as the methods presented in the benchmark.

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Windows

View result in a separate tab

Test name	Executions per second
Array.apply(null, Array(n))	10262.1 Ops/sec
[...Array(n)]	10559.2 Ops/sec
Array(n).fill(null)	10088.3 Ops/sec
Array.from({ length: n })	7899.3 Ops/sec
Array.from({ length:n }, (item, i) => i)	7284.9 Ops/sec

Related benchmarks:

compare the ways to generate a random array for iteration (version: 0)

- Array.apply: Array.apply(null, Array(100)) - Destructuring operator: [...Array(100)] - Array.prototype.fill Array(100).fill(undefined) - Array.from Array.from({ length: 100 })

Comparing performance of: Array.apply(null, Array(n)) vs [...Array(n)] vs Array(n).fill(null) vs Array.from({ length: n }) vs Array.from({ length:n }, (item, i) => i)

Created: 9 months ago by: Guest

Jump to the latest result

Array.apply(null, Array(n))

[...Array(n)]

Array(n).fill(null)

Array.from({ length: n })

Array.from({ length:n }, (item, i) => i)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):