Benchmark Overview

The provided benchmark compares the performance of four ways to create an array in JavaScript: using the new Array() constructor, literal syntax with [], assigning a length to an empty array, and literal syntax with explicit length assignment.

Test Cases

Each test case consists of a single line of code that creates an array with 1000 elements. The code is then executed repeatedly to measure performance.

1. Array Constructor: var arr = new Array(n);
   • This approach creates an empty array and then assigns the length of the array using the n variable.
   • Pros: Simple, straightforward way to create an array.
   • Cons: May incur additional overhead due to the need to assign a length.
2. Literal Syntax: var arr = [];
   • This approach creates an empty array and then uses the push() method to add elements.
   • Pros: Lightweight, efficient way to create an array.
   • Cons: Requires repeated calls to push(), which can be slower than assigning a length.
3. Assign by Index: var arr = [];
   • This approach creates an empty array and then assigns values to each index using the [] syntax.
   • Pros: Simple, straightforward way to create an array with initialized values.
   • Cons: May incur additional overhead due to the need to access and modify individual elements.
4. Explicit Length: var arr = []; arr.length = n;
   • This approach creates an empty array and then assigns a length using the length property.
   • Pros: Efficient way to create an array with a fixed size, as it avoids repeated calls to push().
   • Cons: May incur additional overhead due to the need to access and modify the length property.

Library Used

None of the test cases explicitly use a library. However, some browsers may include libraries or extensions that could affect performance.

Special JS Features/ Syntax

The benchmark does not specifically test any special JavaScript features or syntax, such as async/await, let/const, or arrow functions.

Benchmark Results

The latest benchmark results show the following performance data:

The results indicate that the Array literal (explicit length) approach is the fastest, followed closely by the Array constructor approach.

Alternatives

Other alternatives to create arrays in JavaScript include:

• Using a library like Lodash or Underscore.js to create arrays with various methods and utilities.
• Utilizing the Array.from() method to create an array from an iterable source, such as an array of numbers or strings.
• Leveraging modern JavaScript features like arrow functions or template literals to create arrays with concise syntax.

Keep in mind that the choice of array creation approach depends on specific use cases and performance requirements.