Description

The ArrayBuffer is a core part of JavaScript's low-level binary data manipulation capabilities. It represents a fixed-length raw binary data buffer. This buffer can then be manipulated using views like TypedArray or DataView to handle different types of data.

Why Use ArrayBuffer?

• Performance: Handling binary data directly can be more efficient than processing strings or other high-level objects.
• Interoperability: Facilitates communication with other APIs and systems that require binary formats.
• File Handling: Essential for operations involving file I/O, such as reading and writing binary files.
• Network Operations: Useful for WebSockets and other network protocols that deal with binary data.

Where to Use ArrayBuffer

• WebAssembly: ArrayBuffer is used for interacting with WebAssembly modules, which often require binary data for performance-critical tasks.
• Image Processing: Manipulating pixel data for images, such as applying filters or transformations.
• Audio Processing: Handling raw audio data for playback, analysis, or manipulation.
• Data Storage: Storing and processing binary data, such as in databases or for caching purposes.
• Cryptography: Managing binary data for encryption and decryption processes.
• Scientific Computing: Working with large datasets and complex numerical computations that require efficient binary data handling.

Constructor

The ArrayBuffer constructor creates a new ArrayBuffer object.

let buffer = new ArrayBuffer(8);
console.log(buffer.byteLength); // 8

• Syntax: new ArrayBuffer(length)
• Parameters:
  • length: The size of the buffer in bytes.

Static Properties

• ArrayBuffer.length: Always 1 (the number of arguments the constructor accepts).

console.log(ArrayBuffer.length); // 1

Static Methods

• ArrayBuffer.isView(arg): Returns true if arg is one of the TypedArray or DataView objects.

let buffer = new ArrayBuffer(8);
let view = new Uint8Array(buffer);
console.log(ArrayBuffer.isView(view)); // true

• ArrayBuffer.transfer(oldBuffer, newByteLength): Creates a new ArrayBuffer with the specified size and copies the contents from the old buffer to the new one (experimental).

let buffer1 = new ArrayBuffer(8);
let buffer2 = ArrayBuffer.transfer(buffer1, 16);
console.log(buffer2.byteLength); // 16

Instance Properties

• ArrayBuffer.prototype.byteLength: Returns the length of the ArrayBuffer in bytes.

let buffer = new ArrayBuffer(8);
console.log(buffer.byteLength); // 8

Instance Methods

• ArrayBuffer.prototype.slice(begin, end): Returns a new ArrayBuffer that is a copy of this buffer from begin to end.

let buffer = new ArrayBuffer(8);
let slicedBuffer = buffer.slice(2, 6);
console.log(slicedBuffer.byteLength); // 4

• Parameters:
  • begin: The beginning index of the slice.
  • end: The end index of the slice (not included).

Examples

Example 1: Creating an ArrayBuffer and a TypedArray view

let buffer = new ArrayBuffer(8);
let view = new Uint8Array(buffer);
view[0] = 255;
console.log(view[0]); // 255

Example 2: Using DataView to manipulate data

let buffer = new ArrayBuffer(16);
let view = new DataView(buffer);
view.setUint8(0, 255);
view.setFloat32(4, 42.42, true);
console.log(view.getUint8(0)); // 255
console.log(view.getFloat32(4, true)); // 42.42

Specifications

The ArrayBuffer is defined in the ECMAScript (ECMA-262) specification, ensuring a consistent standard across different JavaScript engines.

Browser Compatibility

The ArrayBuffer is widely supported across all modern browsers, including:

• Chrome
• Firefox
• Safari
• Edge
• Internet Explorer (from version 10)
• Node.js

Conclusion

Understanding and utilizing ArrayBuffer is crucial for efficient binary data manipulation in JavaScript. Whether you're dealing with file I/O, network communication, or performance-critical applications, ArrayBuffer provides a powerful toolset for handling raw binary data.