Science Knowings: JavaScript Course For Social Media

DataView Object

Previously on JavaScript

In our last session, we explored the basics of JavaScript. We learned about variables, data types, and operators. Today, we're diving into a more advanced topic: DataView Object.

What is a DataView Object?

A DataView Object is a view of a binary data buffer that allows you to read and write data at a specific offset. It provides a way to manipulate the underlying binary data without parsing it as strings or numbers.

Creating a DataView Object

To create a DataView Object, you can use the new DataView(buffer, byteOffset, byteLength) constructor, where:

  • buffer is the binary data buffer you want to view.
  • byteOffset (optional) is the offset in bytes from the start of the buffer. Defaults to 0.
  • byteLength (optional) is the length of the view in bytes. Defaults to the remaining buffer size.

DataView Constructor

Syntax:
constructor DataView(buffer, byteOffset, byteLength)
Parameters:
buffer: The binary data buffer to view.
byteOffset (optional): The offset in bytes from the start of the buffer. Defaults to 0.
byteLength (optional): The length of the view in bytes. Defaults to the remaining buffer size.
Returns:
A new DataView Object that provides a view of the specified binary data buffer.

DataView.buffer Property

The DataView.buffer property returns the underlying binary data buffer that the DataView Object is referencing.

DataView.byteOffset Property

The DataView.byteOffset property returns the offset in bytes from the start of the underlying buffer where the DataView Object begins.

DataView.byteLength Property

The DataView.byteLength property returns the length of the DataView Object in bytes.

DataView.get Methods

The DataView.get methods allow you to read data from the binary buffer at the specified offset. They have the following syntax:
get
Type(byteOffset, littleEndian)
Where:
Type is the data type to read, such as Int8, Uint8, Int16, Uint16, Int32, or Uint32.
byteOffset is the offset in bytes from the start of the DataView Object where the read operation should begin.
littleEndian (optional) indicates whether to interpret the data in little-endian (true) or big-endian (false) format. Defaults to false.

DataView.set Methods

The DataView.set methods allow you to write data to the binary buffer at the specified offset. They have the following syntax:
setType(byteOffset, value, littleEndian)
Where:
Type is the data type to write, such as Int8, Uint8, Int16, Uint16, Int32, or Uint32.
byteOffset is the offset in bytes from the start of the DataView Object where the write operation should begin.
value is the value to write to the buffer. littleEndian (optional) indicates whether to interpret the data in little-endian (true) or big-endian (false) format. Defaults to false.

Endianness of DataView

Endianness refers to the order in which bytes are stored in memory. DataView supports both little-endian and big-endian formats. In little-endian format, the least significant byte is stored first, while in big-endian format, the most significant byte is stored first.

DataView.prototype Object

The DataView.prototype object contains the methods and properties that are available to all DataView Objects. These include the get, set, buffer, byteOffset, and byteLength properties.

Big vs Little Endian

Endianness is a term that refers to the order of bytes in computer memory. In little-endian systems, the least significant byte is stored at the lowest memory address, while in big-endian systems, the most significant byte is stored at the lowest memory address.

DataView supports both little-endian and big-endian formats. You can specify the endianness when using the get and set methods.

Use Cases of DataView

DataViews are useful in various scenarios, such as:
  • Reading and writing binary data from files or sockets.
  • Converting between different data types.
  • Manipulating data in a specific format, such as IEEE 754 floating-point numbers.

Next Topic: Working With BigInt

In the next session, we'll explore BigInt, a new data type in JavaScript that allows you to work with arbitrarily large integers. BigInt is especially useful for financial applications and other scenarios where precision is paramount. Follow us to learn more about BigInt and its benefits.