Benchmark: Array creation - 09/08/2018

Tests:

Array.fill
Array(1000).fill(0);
Array.from
Array.from({length: 1000});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.fill
Array.from

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0

Browser/OS: Firefox 56 on Windows 7

View result in a separate tab

Test name	Executions per second
Array.fill	191809.0 Ops/sec
Array.from	11986.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its options.

**Overview**

The provided JSON represents a JavaScript microbenchmark on MeasureThat.net, which compares two approaches for creating an empty array in JavaScript: using the `Array.prototype.fill` method versus using `Array.from`. The benchmark aims to measure the performance difference between these two methods.

**Test Cases**

There are only two test cases:

1. **"Array.fill"`**: This test case uses the `Array.prototype.fill` method to create an empty array of length 1000.
2. **"Array.from"`**: This test case uses the `Array.from` method to create an empty array from an object with a `length` property set to 1000.

**Options Compared**

The two options being compared are:

*   `Array.prototype.fill`: A built-in method in JavaScript that fills all elements of an array with a specified value. In this case, the fill value is `0`.
*   `Array.from`: A built-in method in JavaScript that creates a new array from an iterable (like an object) or an array-like object.

**Pros and Cons**

Here are some pros and cons for each approach:

*   **`Array.prototype.fill`**:
    *   Pros:
        *   Simple and straightforward syntax.
        *   Can be faster since it doesn't create a new array, but rather fills the existing one.
    *   Cons:
        *   Requires JavaScript to know that you want to fill an array with `0`s (or any other value), which might lead to unexpected results if used incorrectly.
*   **`Array.from`**:
    *   Pros:
        *   More flexible syntax, allowing you to create arrays from various iterables or objects.
        *   Can be a good choice when the length of the array isn't known beforehand (e.g., when working with API responses).
    *   Cons:
        *   Slower than `Array.prototype.fill` since it creates a new array.

**Library and Purpose**

In this benchmark, there are no external libraries being used. The benchmark focuses on native JavaScript methods for creating an empty array.

**Special JS Feature or Syntax**

None of the test cases use any special JavaScript features or syntax beyond what's required to create the array.

**Alternatives**

Some alternative approaches to creating an empty array in JavaScript include:

*   Using `Array()`: An older way of creating an array, which is no longer recommended due to its performance and compatibility issues.
*   Using `new Int8Array(0)`, `new Uint8Array(0)`, etc.: These methods create a new typed array with the specified length.

Related benchmarks:

Array creation - 09/08/2018 (version: 0)

Comparison of raw Array creation before calling Array.prototype.fill and Array.from.

Comparing performance of: Array.fill vs Array.from

Created: 6 years ago by: Guest

Jump to the latest result

Array.fill

Array.from

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):