Most efficient way to create a zero filled JavaScript array?

javascript

array-initialization

performance

typed-arrays

byAlex Kataev·Aug 4, 2024

To quickly create a zero-filled array, use Array(10).fill(0):

let zeros = Array(10).fill(0);  // Instantly, a wild array of 10 zeros appears!

Succinct and elegant, this utilizes the fill method in ES6+ to efficiently initialize arrays.

However, remember cooperating with older browsers or handling significant data might require different techniques.

Various Methods for Array Initialization

For zero-filled arrays, JavaScript offers a variety of methods influenced by environment and requirements:

Modern Environments: Using `Array.prototype.fill`

Array.prototype.fill is your go-to method, providing simple and readable code. It was introduced in ES6, so be sure to check the compatibility of your environment.

let zeros = Array(n).fill(0);  // Fill 'er up with zeros!

Performance Handling: Using Typed Arrays

For large arrays, using new Float32Array(n) is extremely speedy as it's a typed array and optimized for numerical data.

let zeros = new Float32Array(n);  // Zooming through array creation at light speed!

For small arrays, combination of a simple loop and new Array(n) proves to be surprisingly quick.

Older environments: Using Polyfills

With polyfills, it's possible to utilize the Array.prototype.fill in older browsers. Always remember to refer to the MDN Web Docs for the polyfill usage.
Alternatively, employing Array(n).join('0').split('').map(Number) can create a numeric zero array.

Leveraging the flexibility of JavaScript

The Power of Typed Arrays:

For numeric computations and hefty data sets:

Utilize typed arrays such as Float32Array and Int32Array to optimize performance, courtesy of their efficient memory usage.

Array Initialization with `Array.from`:

Array.from provides flexibility to initialize arrays using a mapping function, ideal for complex initializations.

let zeros = Array.from({ length: n }, () => 0);  // Trick or treat! Array of zeros!

Crafting arrays with Strings:

For string arrays, a combination of String.prototype.repeat and split can do the trick:

let zeroStrings = new Array(n + 1).join('0').split('');  // Pop, goes the zeroString!

Diving into efficiency and compatibility

Checking Browser Support:

Always ensure your selected methods are compatible with the browser you are working on to enhance usability of your code.

Balancing act between Readability and Performance:

Weigh the readability of your code against its performance impact when picking an array initialization method, especially for scalable applications.

Visualization

Here's a handy conveyor belt analogy. Let's replace boxes being packed with array positions being filled:

Conveyor Belt: [📦, 📦, 📦, 📦, 📦]  // Empty boxes are like undefined array positions

Filling them with zeros is a breeze using Array(n).fill(0):

const zeros = new Array(5).fill(0);  // Conveyor belt in action!

Before: [📦, 📦, 📦, 📦, 📦]  // Conveyor belt with empty boxes
After:  [0️⃣, 0️⃣, 0️⃣, 0️⃣, 0️⃣]  // Conveyor belt filled with zeros. Mission accomplished!

This efficient one-liner fills each box with a zero, getting our entire shipment prepped in no time. 🚀