Diffusion JavaScript API 5.9.24

Class: DataType

diffusion.datatypes. DataType

new DataType()

A data type is specified for a particular value type. It provides methods to convert values to and from binary. Diffusion provides several diffusion.datatypes.DataType implementations.

A data type can optionally support incremental changes to values, represented by one or more types of delta. A delta is the difference between two values. For large or composite values that change in small steps, it is more efficient to transmit an initial value followed by a delta for each change than to transmit a complete value for each change. The data type provides an implementation of diffusion.datatypes.DeltaType for each type of delta it supports via diffusion.datatypes.DataType#deltaType.

Since:
  • 5.7

Methods

deltaType(name, delta) → {diffusion.datatypes.DeltaType}

Obtain a diffusion.datatypes.DeltaType by name or delta type.
Parameters:
Name Type Argument Description
name String <optional>
 The name, as returned by diffusion.datatypes.DeltaType#name
delta Object <optional>
 The delta, from which a type-appropriate dela support will be derived
Returns:
the delta support
Type
diffusion.datatypes.DeltaType
Examples
// Get by name
var deltas = datatype.deltaType("binary");
// Get by type
var deltas = datatype.deltaType(delta);

name() → {String}

The external type identifier.
Returns:
The name of this datatype.
Type
String

readValue(input, offset, length) → {Object}

Parse a value from binary.
Parameters:
Name Type Argument Description
input Buffer The binary data
offset Number <optional>
 The offset to start reading from the provided buffer
length Number <optional>
 The length of the data to read
Throws:
Error if the data is invalid for this type
Returns:
An instance of this data type value
Type
Object

writeValue(value) → {Buffer}

Serialise a value to binary
Parameters:
Name Type Description
value Object The value to serialise
Throws:
Error if the value can not be serialised
Returns:
The serialised value as a buffer
Type
Buffer