//

// Meta.swift

// JSONAPI

//

// Created by Mathew Polzin on 11/21/18.

//

/// Conform a type to this protocol to indicate it can be encoded to or decoded from

/// the meta data attached to a component of a JSON:API document. Different meta data

/// can be stored all over the place: On the root document, on a resource object, on

/// link objects, etc.

///

/// JSON:API Metadata is totally open ended. It can take whatever JSON-compliant structure

/// the server and client agree upon.

public protocol Meta: Codable, Equatable {

// We make Optional a Meta if it wraps a Meta so that

// Metadata can be specified as nullable.

extension Optional: Meta where Wrapped: Meta {}

/// Use this type when you want to specify not to encode or decode any metadata

/// for a type.

public struct NoMetadata: Meta, CustomStringConvertible {

/// The type of metadata found in a Resource Identifier Object.

///

/// It is sometimes more legible to differentiate between types of metadata

/// even when the underlying type is the same. This typealias is only here

/// to make code more easily understandable.

public typealias NoIdMetadata = NoMetadata