Preserve ordering of object properties

.gitignore

@@ -6,3 +6,4 @@ DerivedData/
 .swiftpm/configuration/registries.json
 .swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
 .netrc
+Package.resolved

Package.swift

@@ -9,13 +9,19 @@ let package = Package(
         // Products define the executables and libraries a package produces, making them visible to other packages.
         .library(
             name: "JSONSchema",
-            targets: ["JSONSchema"]),
+            targets: ["JSONSchema"])
+    ],
+    dependencies: [
+        .package(url: "https://github.com/apple/swift-collections.git", from: "1.0.0")
     ],
     targets: [
         // Targets are the basic building blocks of a package, defining a module or a test suite.
         // Targets can depend on other targets in this package and products from dependencies.
         .target(
-            name: "JSONSchema"),
+            name: "JSONSchema",
+            dependencies: [
+                .product(name: "OrderedCollections", package: "swift-collections")
+            ]),
         .testTarget(
             name: "JSONSchemaTests",
             dependencies: ["JSONSchema"]

Sources/JSONSchema/JSONSchema.swift

@@ -1,3 +1,6 @@
+import Foundation
+import OrderedCollections
+
 /// A type that represents a JSON Schema definition.
 ///
 /// Use JSONSchema to create, manipulate, and encode/decode JSON Schema documents.
@@ -41,7 +44,7 @@
         enum: [JSONValue]? = nil,
         const: JSONValue? = nil,
         /*  */
-        properties: [String: JSONSchema] = [:],
+        properties: OrderedDictionary<String, JSONSchema> = [:],
         required: [String] = [],
         additionalProperties: AdditionalProperties? = nil
     )
@@ -677,7 +680,8 @@ extension JSONSchema: Codable {
         switch type {
         case "object":
             let properties =
-                try container.decodeIfPresent([String: JSONSchema].self, forKey: .properties) ?? [:]
+                try container.decodeIfPresent(
+                    OrderedDictionary<String, JSONSchema>.self, forKey: .properties) ?? [:]
             let required = try container.decodeIfPresent([String].self, forKey: .required) ?? []
             let additionalProperties = try container.decodeIfPresent(
                 AdditionalProperties.self, forKey: .additionalProperties)