Benchmark: Create Array Filled with Undefined

Script Preparation code:

var length = 10000;

Tests:

Array.apply
const array = Array.apply(null, { length });
Array.concat
const array = [].concat.apply([], { length });
Array.fill
const array = []; array.length = length; array.fill(undefined);
Custom function
const func = (...args) => args; func.apply(null, { length });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.apply
Array.concat
Array.fill
Custom function

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.0.0 Safari/537.36

Browser/OS: Chrome 102 on Windows

View result in a separate tab

Test name	Executions per second
Array.apply	3652.1 Ops/sec
Array.concat	3052.9 Ops/sec
Array.fill	36809.0 Ops/sec
Custom function	3946.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided JSON benchmark.

**Benchmark Definition:**

The benchmark defines how to create an array filled with `undefined` values. There are four different approaches:

1. **`Array.apply(null, { length })`**: This method creates a new array object and then applies the `length` property to it using the `apply()` method.
2. **`Array.concat.apply([], { length })`**: This method uses the `concat()` method to create an empty array, and then applies the `length` property to it using the `apply()` method.
3. **`Array.fill(undefined)`**: This method simply sets all elements of the existing array to `undefined` using the `fill()` method.
4. **Custom function (`const func = (...args) => args; func.apply(null, { length });`)**: This is a custom function that creates an empty array and then applies the `length` property to it using the `apply()` method.

**Options compared:**

The benchmark compares the performance of these four approaches:

* **`Array.fill()`**: A simple and efficient way to create an array filled with values.
* **Custom function**: A custom implementation that creates an empty array and then applies the `length` property to it using the `apply()` method.

**Pros and Cons:**

1. **`Array.fill(undefined)`**:
	* Pros: Simple, efficient, and widely supported (all modern browsers).
	* Cons: May not be suitable for large arrays or performance-critical applications.
2. **Custom function (`const func = (...args) => args; ...`)**:
	* Pros: Allows for fine-grained control over array creation and can be optimized for specific use cases.
	* Cons: Requires more code and may have additional overhead due to the custom implementation.

**Library/Functionality used:**

None of the approaches require any external libraries or functions beyond what's built into JavaScript.

**Special JS features or syntax:**

None of the approaches rely on any special JavaScript features or syntax. However, it's worth noting that `Array.fill()` is a relatively modern feature (introduced in ECMAScript 2015) and may not be supported in older browsers.

**Other alternatives:**

If you need to create an array filled with values for performance-critical applications, you could also consider using:

* **`Buffer.alloc()`**: For creating a buffer filled with zeros or other values.
* **`TypedArray` constructors**: Such as `Int8Array`, `Uint8Array`, etc., which can be used to create arrays of specific types and sizes.

Keep in mind that these alternatives may have different performance characteristics and use cases compared to the approaches tested in this benchmark.

Related benchmarks:

Create Array Filled with Undefined (version: 0)

Comparing performance of: Array.apply vs Array.concat vs Array.fill vs Custom function

Created: 3 years ago by: Guest

Jump to the latest result

Array.apply

Array.concat

Array.fill

Custom function

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):