Typed Arrays are a powerful feature in JavaScript that allow you to work with data in a more efficient and controlled manner. In this article, we will explore what Typed Arrays are and how to use them effectively.

The Basics

JavaScript provides eight types of Typed Arrays:

  • Int8Array: an array of 8-bit signed integers
  • Int16Array: an array of 16-bit signed integers
  • Int32Array: an array of 32-bit signed integers
  • Uint8Array: an array of 8-bit unsigned integers
  • Uint16Array: an array of 16-bit unsigned integers
  • Uint32Array: an array of 32-bit unsigned integers
  • Float32Array: an array of 32-bit floating point numbers
  • Float64Array: an array of 64-bit floating point numbers

All Typed Array types are instances of the ArrayBufferView class, which allows you to view and manipulate data stored in an ArrayBuffer.

Creating Typed Arrays

To create a Typed Array, you can use the new keyword followed by the desired type. For example, to create an array of 8-bit signed integers:

const a = new Int8Array()

You can also pre-allocate a specific number of bytes for the array:

const bytes = 1024
const a = new Int8Array(bytes)

Accessing Data

Typed Arrays provide a way to access the content of an ArrayBuffer. After creating a Typed Array, you can assign an ArrayBuffer to it:

// We have an existing `buffer` ArrayBuffer
const a = new Int8Array(buffer)

Once you have access to the content of the ArrayBuffer, you can manipulate the data using the familiar array access techniques. Typed Arrays also provide a wide range of methods and properties, including map() and reduce().

Use Cases

The main use cases for Typed Arrays are for working with technologies like WebGL, Web Audio, and the Canvas API. These technologies often expect Typed Arrays as input, as they offer superior performance compared to regular JavaScript arrays.

Endianness Considerations

It’s important to note that Typed Arrays use the byte order of the platform and do not allow you to control endianness. This is usually not a problem, as most platforms use the little endian byte order. However, if you need explicit control over endianness, you can use the DataView class instead.

Typed Arrays are a valuable tool for developers working with multimedia APIs and performance-sensitive applications. Understanding how to use them effectively can greatly enhance your JavaScript skills.