Benchmark: Array Initialization Types v4

Script Preparation code:

var times = 5000;

Tests:

Array Constructor
var a = new Array(); for (var i = 0; i <= times; i++) { a.push(1337) }
Array Size Constructor
var b = new Array(times); for (var i = 0; i <= times; i++) { b.push(1337) }
Array Literal
var c = []; for (var i = 0; i <= times; i++) { c.push(1337) }
Fill Map
new Array(times).fill().map((_arg) => 1337)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array Constructor
Array Size Constructor
Array Literal
Fill Map

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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Let's break down the provided benchmark and its test cases.

**Benchmark Overview**

The benchmark is designed to measure the performance of different approaches for initializing arrays in JavaScript. There are four test cases:

1.  **Array Constructor**: Creates an array using the `new Array()` constructor and pushes elements into it.
2.  **Array Size Constructor**: Creates an array with a specified size using the `new Array(size)` constructor and then fills it with elements.
3.  **Array Literal**: Creates an array using the literal syntax (`[]`) and pushes elements into it.
4.  **Fill Map**: Uses the `fill` method in combination with the `map` function to create an array.

**Options Comparison**

Here's a comparison of the options:

*   **Array Constructor**: Pros - simple and straightforward, widely supported. Cons - can be slower than other methods due to the overhead of creating a new array object.
*   **Array Size Constructor**: Pros - more efficient than `new Array()` since it pre-allocates memory for the array elements. Cons - requires specifying the size, which might not always be known at compile-time.
*  **Array Literal**: Pros - concise and easy to read, widely supported. Cons - can lead to slower performance due to the overhead of creating a new array object.
*   **Fill Map**: Pros - uses existing functions (`fill` and `map`) which are optimized for performance. Cons - might be less readable than other methods.

**Library Usage**

None of the test cases explicitly use any external libraries, but they do utilize built-in JavaScript features:

*   The `push` method is used to add elements to an array.
*   The `fill` and `map` functions are used in the "Fill Map" test case.
*   The `new Array()` constructor is used in two test cases.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax mentioned in the benchmark definition. However, some older browsers might have issues with these syntaxes:

*   `var` and `let`/`const` declarations (not explicitly used here but could be relevant for other tests).
*   Arrow functions (`=>`) are used in the "Fill Map" test case.

**Alternative Approaches**

Other approaches to initializing arrays in JavaScript include:

*   Using `Array.from()` method, which creates a new array from an iterable.
*   Using a `for...of` loop or a `forEach` function (not explicitly mentioned here).
*   Creating an empty array using `[] = []`, but this is not as explicit as the four methods in this benchmark.

In conclusion, this benchmark provides a straightforward and concise way to compare the performance of different approaches for initializing arrays in JavaScript. It allows users to easily see how their preferred method stacks up against others, making it easier to identify potential bottlenecks or areas where optimization might be possible.

Related benchmarks:

Array Initialization Types v4 (version: 0)

Comparing performance of: Array Constructor vs Array Size Constructor vs Array Literal vs Fill Map

Created: 3 years ago by: Guest

Jump to the latest result

Array Constructor

Array Size Constructor

Array Literal

Fill Map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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