Support SelectionSet to receive [String: Any] for initialization when…

… create mock object (apollographql/apollo-ios-dev#102)

Sources/Apollo/SelectionSet+DictionaryIntializer.swift

@@ -0,0 +1,69 @@
+#if !COCOAPODS
+import ApolloAPI
+#endif
+
+public enum RootSelectionSetInitializeError: Error {
+  case hasNonHashableValue
+}
+
+extension RootSelectionSet {
+  /// Initializes a `SelectionSet` with a raw JSON response object.
+  ///
+  /// The process of converting a JSON response into `SelectionSetData` is done by using a
+  /// `GraphQLExecutor` with a`GraphQLSelectionSetMapper` to parse, validate, and transform
+  /// the JSON response data into the format expected by `SelectionSet`.
+  ///
+  /// - Parameters:
+  ///   - data: A dictionary representing a JSON response object for a GraphQL object.
+  ///   - variables: [Optional] The operation variables that would be used to obtain
+  ///                the given JSON response data.
+  @_disfavoredOverload
+  public init(
+    data: [String: Any],
+    variables: GraphQLOperation.Variables? = nil
+  ) throws {
+    let jsonObject = try Self.convertToAnyHashableValueDict(dict: data)
+    try self.init(data: jsonObject, variables: variables)
+  }
+
+  /// Convert dictionary type [String: Any] to [String: AnyHashable]
+  /// - Parameter dict: [String: Any] type dictionary
+  /// - Returns: converted [String: AnyHashable] type dictionary
+  private static func convertToAnyHashableValueDict(dict: [String: Any]) throws -> [String: AnyHashable] {
+    var result = [String: AnyHashable]()
+
+    for (key, value) in dict {
+      if let arrayValue = value as? [Any] {
+        result[key] = try convertToAnyHashableArray(array: arrayValue)
+      } else  {
+        if let dictValue = value as? [String: Any] {
+          result[key] = try convertToAnyHashableValueDict(dict: dictValue)
+        } else if let hashableValue = value as? AnyHashable {
+          result[key] = hashableValue
+        } else {
+          throw RootSelectionSetInitializeError.hasNonHashableValue
+        }
+      }
+    }
+    return result
+  }
+
+  /// Convert Any type Array type to AnyHashable type Array
+  /// - Parameter array: Any type Array
+  /// - Returns: AnyHashable type Array
+  private static func convertToAnyHashableArray(array: [Any]) throws -> [AnyHashable] {
+    var result: [AnyHashable] = []
+    for value in array {
+      if let array = value as? [Any] {
+        result.append(try convertToAnyHashableArray(array: array))
+      } else if let dict = value as? [String: Any] {
+        result.append(try convertToAnyHashableValueDict(dict: dict))
+      } else if let hashable = value as? AnyHashable {
+        result.append(hashable)
+      } else {
+        throw RootSelectionSetInitializeError.hasNonHashableValue
+      }
+    }
+    return result
+  }
+}