Diffusion JavaScript API 6.1.5

Class: BinaryDataType

diffusion.datatypes. BinaryDataType

new BinaryDataType()

Binary data type.

Accessed via: diffusion.datatypes.binary();

The implementation provides support for binary deltas.

diffusion.datatypes.Binary values can be used to store and transmit arbitrary information. The responsibility for formatting and interpreting the information belongs solely to the application. Before using Binary for a topic, consider other data types such as JSON or single value topic types; these may provide a simpler interface for your application.

Properties:
Name Type Description
diffusion.datatypes.BinaryDataType.Binary diffusion.datatypes.Binary The Binary data type value class
Since:
  • 5.7

Extends

Methods

canReadAs(valueType) → {Boolean}

Test whether this data type is compatible with valueType. Compatibility with a valueType means than any valid binary representation of a value can be read as an instance of valueType.

Every data type should be compatible with the following:

  • Value Type – the class corresponding to the data type's value type.

For a data type with a value type of X, readAs(X, buffer) is equivalent to readValue(buffer).

Parameters:
Name Type Description
valueType function the type to check
Since:
  • 6.0
Inherited From:
Returns:
true if a binary representation created by this data type can read as an instance of valueType
Type
Boolean

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 delta support will be derived
Inherited From:
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);

from(buffer) → {diffusion.datatypes.Binary}

Returns a new diffusion.datatypes.Binary instance from a buffer.
Parameters:
Name Type Description
buffer Buffer The binary data
Returns:
a Binary data-type instance
Type
diffusion.datatypes.Binary

name() → {String}

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

readAs(valueType, buffer, offset, length) → {Object}

Create a value of a compatible class from binary.
Parameters:
Name Type Argument Default Description
valueType function the type of the result
buffer Buffer the binary data
offset Number <optional>
 0 the offset to read data from the buffer
length Number <optional>
 buffer.length the length of data to read from the buffer
Since:
  • 6.0
Inherited From:
Throws:
Error if valueType is incompatible with this data type, or buffer does not represent a valid value.
Returns:
the value in the form of the specified type
Type
Object

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
Inherited From:
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
Inherited From:
Throws:
Error if the value can not be serialised
Returns:
The serialised value as a buffer
Type
Buffer