feat: Adds default value support

Author: NeedleInAJayStack

Examples/HelloWorldServer/Sources/HelloWorldServer/schema.graphql

@@ -14,7 +14,7 @@ input UserInfo {
   name: String!
   email: EmailAddress!
   age: Int
-  role: Role
+  role: Role = USER
 }
 
 """

Examples/HelloWorldServer/Tests/HelloWorldServerTests/HelloWorldServerTests.swift

@@ -11,45 +11,45 @@ struct HelloWorldServerTests {
             users: ["1" : .init(id: "1", name: "John", email: "john@example.com", age: 18, role: .user)],
             posts: ["1" : .init(id: "1", title: "Foo", content: "bar", authorId: "1")]
         )
-        #expect(
-            try await graphql(
-                schema: schema,
-                request: """
-                {
-                    posts {
+        let actual = try await graphql(
+            schema: schema,
+            request: """
+            {
+                posts {
+                    id
+                    title
+                    content
+                    author {
                         id
-                        title
-                        content
-                        author {
-                            id
-                            name
-                            email
-                            age
-                            role
-                        }
+                        name
+                        email
+                        age
+                        role
                     }
                 }
-                """,
-                context: context
-            ) == .init(
-                data: [
-                    "posts": [
-                        [
+            }
+            """,
+            context: context
+        )
+        let expected = GraphQLResult(
+            data: [
+                "posts": [
+                    [
+                        "id": "1",
+                        "title": "Foo",
+                        "content": "bar",
+                        "author": [
                             "id": "1",
-                            "title": "Foo",
-                            "content": "bar",
-                            "author": [
-                                "id": "1",
-                                "name": "John",
-                                "email": "john@example.com",
-                                "age": 18,
-                                "role": "USER"
-                            ]
+                            "name": "John",
+                            "email": "john@example.com",
+                            "age": 18,
+                            "role": "USER"
                         ]
                     ]
                 ]
-            )
+            ]
         )
+        #expect(actual == expected)
     }
 
     @Test func mutation() async throws {
@@ -58,32 +58,32 @@ struct HelloWorldServerTests {
             users: [:],
             posts: [:]
         )
-        #expect(
-            try await graphql(
-                schema: schema,
-                request: """
-                mutation {
-                    upsertUser(userInfo: {id: "2", name: "Jane", email: "jane@example.com"}) {
-                        id
-                        name
-                        email
-                        age
-                        role
-                    }
+        let actual = try await graphql(
+            schema: schema,
+            request: """
+            mutation {
+                upsertUser(userInfo: {id: "2", name: "Jane", email: "jane@example.com"}) {
+                    id
+                    name
+                    email
+                    age
+                    role
                 }
-                """,
-                context: context
-            ) == .init(
-                data: [
-                    "upsertUser": [
-                        "id": "2",
-                        "name": "Jane",
-                        "email": "jane@example.com",
-                        "age": nil,
-                        "role": nil
-                    ]
+            }
+            """,
+            context: context
+        )
+        let expected = GraphQLResult(
+            data: [
+                "upsertUser": [
+                    "id": "2",
+                    "name": "Jane",
+                    "email": "jane@example.com",
+                    "age": nil,
+                    "role": "USER"
                 ]
-            )
+            ]
         )
+        #expect(actual == expected)
     }
 }

README.md

@@ -217,12 +217,11 @@ public struct EmailAddress: Scalar {
 
 ## Development Roadmap
 
-1. Default values: Default values are currently ignored
-2. Directives: Directives are currently not supported
-3. Subscription: Subscription definitions are currently ignored
-4. Improved testing: Generator tests should cover much more of the functionality
-5. Additional examples: Ideally large ones that cover significant GraphQL features
-6. Executable Schema: To work around the immutability of some Schema components, we generate Swift code to fully recreate the defined schema. Instead, we could just add resolver logic to the schema parsed from the `.graphql` file SDL.
+1. Directives: Directives are currently not supported
+2. Subscription: Subscription definitions are currently ignored
+3. Improved testing: Generator tests should cover much more of the functionality
+4. Additional examples: Ideally large ones that cover significant GraphQL features
+5. Executable Schema: To work around the immutability of some Schema components, we generate Swift code to fully recreate the defined schema. Instead, we could just add resolver logic to the schema parsed from the `.graphql` file SDL.
 
 ## Contributing
 

Sources/GraphQLGeneratorCore/Generator/SchemaGenerator.swift

@@ -285,7 +285,12 @@ package struct SchemaGenerator {
                         type: \(try graphQLTypeReference(for: field.type)),
             """
 
-            // TODO: Default value support
+            if let defaultValue = field.defaultValue {
+                output += """
+
+                            defaultValue: \(mapToSwiftCode(defaultValue)),
+                """
+            }
 
             if let description = field.description {
                 output += """
@@ -660,6 +665,13 @@ package struct SchemaGenerator {
                     """
                 }
 
+                if let defaultValue = arg.defaultValue {
+                    output += """
+                    ,
+                            defaultValue: \(mapToSwiftCode(defaultValue))
+                    """
+                }
+
                 output += """
 
                         ),

Sources/GraphQLGeneratorCore/Utilities/swiftTypeName.swift

@@ -81,3 +81,37 @@ func mapScalarType(_ graphQLType: String, nameGenerator: SafeNameGenerator) -> S
         return nameGenerator.swiftTypeName(for: graphQLType)
     }
 }
+
+/// Converts a Map value to valid Swift code representation
+func mapToSwiftCode(_ map: Map) -> String {
+    switch map {
+    case .undefined:
+        return ".undefined"
+    case .null:
+        return ".null"
+    case .bool(let value):
+        return ".bool(\(value))"
+    case .number(let value):
+        return ".number(Number(\(value)))"
+    case .string(let value):
+        // Escape special characters for Swift string literal
+        let escaped = value
+            .replacingOccurrences(of: "\\", with: "\\\\")
+            .replacingOccurrences(of: "\"", with: "\\\"")
+            .replacingOccurrences(of: "\n", with: "\\n")
+            .replacingOccurrences(of: "\r", with: "\\r")
+            .replacingOccurrences(of: "\t", with: "\\t")
+        return ".string(\"\(escaped)\")"
+    case .array(let values):
+        let elements = values.map { mapToSwiftCode($0) }.joined(separator: ", ")
+        return ".array([\(elements)])"
+    case .dictionary(let dict):
+        let pairs = dict.map { key, value in
+            let escapedKey = key
+                .replacingOccurrences(of: "\\", with: "\\\\")
+                .replacingOccurrences(of: "\"", with: "\\\"")
+            return "\"\(escapedKey)\": \(mapToSwiftCode(value))"
+        }.joined(separator: ", ")
+        return ".dictionary([\(pairs)])"
+    }
+}