✨ Add "id" to Feature

Author: RemiBardon

Sources/GeoJSON/FeatureProperties.swift

@@ -375,12 +375,13 @@ extension AnyBoundingBox {
 
 fileprivate enum FeatureCodingKeys: String, CodingKey {
 	case geoJSONType = "type"
-	case geometry, properties, bbox
+	case id, geometry, properties, bbox
 }
 
 extension Feature {
 
 	public init(from decoder: Decoder) throws {
+		print(String(describing: ID.self))
 		let container = try decoder.container(keyedBy: FeatureCodingKeys.self)
 
 		let type = try container.decode(GeoJSON.`Type`.self, forKey: .geoJSONType)
@@ -391,16 +392,18 @@ extension Feature {
 			))
 		}
 
+		let id = try container.decodeIfPresent(ID.self, forKey: .id)
 		let geometry = try container.decodeIfPresent(Geometry.self, forKey: .geometry)
 		let properties = try container.decode(Properties.self, forKey: .properties)
 
-		self.init(geometry: geometry, properties: properties)
+		self.init(id: id, geometry: geometry, properties: properties)
 	}
 
 	public func encode(to encoder: Encoder) throws {
 		var container = encoder.container(keyedBy: FeatureCodingKeys.self)
 
 		try container.encode(Self.geoJSONType, forKey: .geoJSONType)
+		try container.encodeIfPresent(self.id, forKey: .id)
 		try container.encodeIfPresent(self.geometry, forKey: .geometry)
 		try container.encode(self.properties, forKey: .properties)
 		// TODO: Create GeoJSONEncoder that allows setting "export bboxes" to a boolean value
@@ -429,7 +432,7 @@ extension FeatureCollection {
 		}
 
 		let features = try container.decodeIfPresent(
-			[Feature<Geometry, Properties>].self,
+			[Feature<ID, Geometry, Properties>].self,
 			forKey: .features
 		) ?? []
 

Sources/GeoJSON/GeoJSON+Codable.swift

@@ -0,0 +1,9 @@
+//
+//  NonID.swift
+//  GeoSwift
+//
+//  Created by Rémi Bardon on 09/02/2022.
+//  Copyright © 2022 Rémi Bardon. All rights reserved.
+//
+
+public typealias NonID = Bool

Sources/GeoJSON/Helpers/NonID.swift

@@ -8,23 +8,53 @@
 
 /// A [GeoJSON Feature](https://datatracker.ietf.org/doc/html/rfc7946#section-3.2).
 public struct Feature<
+	ID: Codable,
 	Geometry: GeoJSON.Geometry & Codable,
-	Properties: GeoJSON.FeatureProperties
+	Properties: Codable
 >: CodableObject {
 
 	public static var geoJSONType: GeoJSON.`Type` { .feature }
 
 	public var bbox: Geometry.BoundingBox? { geometry?.bbox }
 
+	public var id: ID?
 	public var geometry: Geometry?
+	/// The `"properties"` field of a [GeoJSON Feature](https://datatracker.ietf.org/doc/html/rfc7946#section-3.2).
 	public var properties: Properties
 
-	public init(geometry: Geometry?, properties: Properties) {
+	public init(id: ID?, geometry: Geometry?, properties: Properties) {
+		self.id = id
 		self.geometry = geometry
 		self.properties = properties
 	}
 
+	public init(geometry: Geometry?, properties: Properties) where ID == NonID {
+		self.id = nil
+		self.geometry = geometry
+		self.properties = properties
+	}
+	
+}
+
+extension Feature: Identifiable where ID: Hashable {}
+extension Feature: Equatable where ID: Equatable, Properties: Equatable {
+	
+	public static func == (lhs: Self, rhs: Self) -> Bool {
+		return lhs.id == rhs.id
+		&& lhs.geometry == rhs.geometry
+		&& lhs.properties == rhs.properties
+	}
+	
+}
+extension Feature: Hashable where ID: Hashable, Properties: Hashable {
+	
+	public func hash(into hasher: inout Hasher) {
+		hasher.combine(id)
+		hasher.combine(geometry)
+		hasher.combine(properties)
+	}
+	
 }
 
 /// A (half) type-erased ``Feature``.
-public typealias AnyFeature<Properties: GeoJSON.FeatureProperties> = Feature<AnyGeometry, Properties>
+public typealias AnyFeature<Properties: Codable> = Feature<NonID, AnyGeometry, Properties>

Sources/GeoJSON/Objects/Feature.swift

@@ -8,20 +8,37 @@
 
 /// A [GeoJSON FeatureCollection](https://datatracker.ietf.org/doc/html/rfc7946#section-3.3).
 public struct FeatureCollection<
+	ID: Codable,
 	Geometry: GeoJSON.Geometry & Codable,
-	Properties: GeoJSON.FeatureProperties
+	Properties: Codable
 >: CodableObject {
 
 	public static var geoJSONType: GeoJSON.`Type` { .featureCollection }
 
-	public var features: [Feature<Geometry, Properties>]
+	public var features: [Feature<ID, Geometry, Properties>]
 
 	// FIXME: Fix bounding box
 	public var bbox: AnyBoundingBox? { nil }
 
 }
 
+extension FeatureCollection: Equatable where ID: Equatable, Properties: Equatable {
+	
+	public static func == (lhs: Self, rhs: Self) -> Bool {
+		return lhs.features == rhs.features
+	}
+	
+}
+
+extension FeatureCollection: Hashable where ID: Hashable, Properties: Hashable {
+	
+	public func hash(into hasher: inout Hasher) {
+		hasher.combine(features)
+	}
+	
+}
+
 /// A (half) type-erased ``FeatureCollection``.
 public typealias AnyFeatureCollection<
-	Properties: GeoJSON.FeatureProperties
-> = FeatureCollection<AnyGeometry, Properties>
+	Properties: Codable
+> = FeatureCollection<NonID, AnyGeometry, Properties>

Sources/GeoJSON/Objects/FeatureCollection.swift

@@ -9,7 +9,7 @@
 import Turf
 
 /// A [GeoJSON Geometry](https://datatracker.ietf.org/doc/html/rfc7946#section-3.1).
-public protocol Geometry: GeoJSON.Object {
+public protocol Geometry: GeoJSON.Object, Hashable {
 
 	var bbox: BoundingBox? { get }
 

Sources/GeoJSON/Objects/Geometry.swift

@@ -7,7 +7,7 @@
 //
 
 /// A [GeoJSON Object](https://datatracker.ietf.org/doc/html/rfc7946#section-3).
-public protocol Object: Hashable {
+public protocol Object {
 
 	associatedtype BoundingBox: GeoJSON.BoundingBox
 

Sources/GeoJSON/Objects/Object.swift

@@ -170,7 +170,7 @@ final class GeoJSONDecodableTests: XCTestCase {
 		].joined()
 
 		let data: Data = try XCTUnwrap(string.data(using: .utf8))
-		let feature = try JSONDecoder().decode(Feature<Point2D, FeatureProperties>.self, from: data)
+		let feature = try JSONDecoder().decode(Feature<NonID, Point2D, FeatureProperties>.self, from: data)
 
 		let expected: Feature = Feature(
 			geometry: Point2D(coordinates: .nantes),
@@ -179,6 +179,33 @@ final class GeoJSONDecodableTests: XCTestCase {
 		XCTAssertEqual(feature, expected)
 	}
 
+	func testFeature2DWithIDDecode() throws {
+		struct FeatureProperties: Hashable, Codable {}
+		
+		let string: String = [
+			"{",
+				"\"type\":\"Feature\",",
+				"\"id\":\"feature_id\",",
+				"\"geometry\":{",
+					"\"type\":\"Point\",",
+					"\"coordinates\":[-1.55366,47.21881]",
+				"},",
+				"\"properties\":{},",
+				"\"bbox\":[-1.55366,47.21881,-1.55366,47.21881]",
+			"}",
+		].joined()
+		
+		let data: Data = try XCTUnwrap(string.data(using: .utf8))
+		let feature = try JSONDecoder().decode(Feature<String, Point2D, FeatureProperties>.self, from: data)
+		
+		let expected: Feature = Feature(
+			id: "feature_id",
+			geometry: Point2D(coordinates: .nantes),
+			properties: FeatureProperties()
+		)
+		XCTAssertEqual(feature, expected)
+	}
+	
 	// MARK: Real-world use cases
 
 	func testDecodeFeatureProperties() throws {

Tests/GeoJSONTests/GeoJSON+DecodableTests.swift

@@ -163,4 +163,32 @@ final class GeoJSONEncodableTests: XCTestCase {
 		XCTAssertEqual(string, expected)
 	}
 
+	func testFeature2DWithIDEncode() throws {
+		struct FeatureProperties: Hashable, Codable {}
+		
+		let feature: Feature = Feature(
+			id: "feature_id",
+			geometry: Point2D(coordinates: .nantes),
+			properties: FeatureProperties()
+		)
+		let data: Data = try JSONEncoder().encode(feature)
+		let string: String = try XCTUnwrap(String(data: data, encoding: .utf8))
+		
+		let expected: String = [
+			"{",
+				// For some reason, `"id"` goes here 🤷
+				"\"id\":\"feature_id\",",
+				// For some reason, `"properties"` goes here 🤷
+				"\"properties\":{},",
+				"\"type\":\"Feature\",",
+				"\"geometry\":{",
+					"\"type\":\"Point\",",
+					"\"coordinates\":[-1.55366,47.21881]",
+				"},",
+				"\"bbox\":[-1.55366,47.21881,-1.55366,47.21881]",
+			"}",
+		].joined()
+		XCTAssertEqual(string, expected)
+	}
+	
 }