add minimal inheritance support

lib/fields-metadata/FieldsMetadata.ts

@@ -1,21 +1,51 @@
 import 'reflect-metadata';
-import {metadataGet, metadataGetOrSet} from "../utils/metadataFactories";
+import {metadataGet} from "../utils/metadataFactories";
 import {FieldConfig} from "./FieldConfig";
+import {getSuperClass} from "../utils/core";
 
 const FIELDS_METADATA_KEY = '__FIELDS_METADATA_KEY';
 
 export class FieldsMetadata {
     static getForClass = metadataGet<FieldsMetadata>(FIELDS_METADATA_KEY);
-    static getOrCreateForClass = metadataGetOrSet(FIELDS_METADATA_KEY, FieldsMetadata);
+    static getOrCreateForClass(klass):FieldsMetadata {
+        let attributesMetadata = Reflect.getOwnMetadata(FIELDS_METADATA_KEY, klass);
 
+        if (!attributesMetadata) {
+            attributesMetadata = new FieldsMetadata();
+            Reflect.defineMetadata(FIELDS_METADATA_KEY, attributesMetadata, klass);
 
-    protected _fields:{ [fieldName:string]:FieldConfig } = {};
+
+            let superClass = getSuperClass(klass);
+            if (superClass) {
+                attributesMetadata.setParent(FieldsMetadata.getOrCreateForClass(superClass));
+            }
+        }
+
+        return attributesMetadata;
+    }
+
+
+    private parent:FieldsMetadata;
+    protected _ownFields:{ [fieldName:string]:FieldConfig } = {};
 
     getField(fieldName:string):FieldConfig {
-        return this._fields[fieldName] || (this._fields[fieldName] = new FieldConfig())
+        return this._ownFields[fieldName] || (this._ownFields[fieldName] = new FieldConfig())
     }
 
     getFields():{ [fieldName:string]:FieldConfig } {
-        return this._fields;
+        let parentFields = this.parent ? this.parent.getFields() : {};
+
+        //TODO: consider deep merge of field configuration. In current implementation ownField configuration overrides completely field config from parent
+        return {
+            ...parentFields,
+            ...this._ownFields
+        }
     }
-}
+
+    private setParent(fieldsMetadata:FieldsMetadata) {
+        this.parent = fieldsMetadata;
+    }
+}
+
+
+

lib/fields-metadata/TypeValue.ts

@@ -5,6 +5,8 @@ export class TypeValue<T> {
     private _type:T;
     private _typeThunk:Thunk<T>;
 
+    //TODO: validate if both _type and _typeThunk are being set
+
     setType(type:T) {
         this._type = type;
     }

lib/utils/core.ts

@@ -25,6 +25,11 @@ export function invariant(condition:boolean, message:string) {
     }
 }
 
+export function getSuperClass(klass) {
+    let superClass = Object.getPrototypeOf(klass);
+    return superClass.name ? superClass : null;
+}
+
 export function propagateErrorWithContext<T>(ctx:string, fn:() => T):T {
     try {
         return fn();

spec/fields-metadata/FieldsMetadata.spec.ts

@@ -0,0 +1,25 @@
+import {FieldsMetadata} from "../../lib/fields-metadata/FieldsMetadata";
+import {GraphQLString} from "graphql";
+import {expect} from 'chai'
+
+describe(`FieldsMetadata`, () => {
+    describe('inheritance', () => {
+        class ParentClass {}
+
+        let fieldsMetadata = FieldsMetadata.getOrCreateForClass(ParentClass);
+        let parentField = fieldsMetadata.getField('parentField');
+        parentField.setType(GraphQLString);
+        parentField.setDescription('Parent Field Description');
+
+        it('inherits all parent class properties', () => {
+            class ChildClass extends ParentClass {}
+
+            let fieldsMetadata = FieldsMetadata.getOrCreateForClass(ChildClass);
+            let fields = fieldsMetadata.getFields();
+
+            expect(fields).to.have.keys(['parentField']);
+        });
+
+        //TODO: add more test cases
+    })
+});

spec/integration/inheritance.spec.ts

@@ -0,0 +1,146 @@
+import {buildASTSchema, GraphQLInt, GraphQLString, parse, printType} from "graphql";
+import {expect} from 'chai';
+import {GraphQLSchema} from "graphql/type/schema";
+import {createSchema, field, id, list, nonNull, nonNullItems, type} from "../../lib";
+
+
+@type()
+class Mutation {
+    @field(GraphQLString)
+    unused:string;
+}
+
+
+@type()
+class ListResult {
+    @field(GraphQLInt) @nonNull()
+    totalCount:number;
+}
+
+@type()
+class PersistedObject {
+    @id() @nonNull()
+    id:string;
+
+    @field(GraphQLInt)
+    createdAt:number; //for simplification store as integer timestamp instead of custom scalar
+
+    @field(GraphQLInt)
+    updatedAt:number; //for simplification store as integer timestamp instead of custom scalar
+}
+
+@type()
+class User extends PersistedObject {
+    @field(GraphQLString)
+    email:string
+}
+
+@type()
+class UsersList extends ListResult {
+    @list(User) @nonNull() @ nonNullItems()
+    users:User[]
+}
+
+@type()
+class Product extends PersistedObject {
+    @field(GraphQLString)
+    productName:string
+}
+
+@type()
+class ProductsList extends ListResult {
+    @list(Product) @nonNull() @ nonNullItems()
+    products:Product[]
+}
+
+
+@type()
+class Query {
+    @field(UsersList) @nonNull()
+    users:UsersList;
+
+    @field(ProductsList) @nonNull()
+    products:ProductsList;
+}
+
+
+function createdSchemaFromDecoratedClasses():GraphQLSchema {
+    return createSchema(Query, Mutation);
+}
+
+function createSchemaFromDefinition():GraphQLSchema {
+    const definition = `
+            type User {
+                id: ID!
+                createdAt: Int
+                updatedAt: Int
+                email: String
+            }
+            
+            type Product {
+                id: ID!
+                createdAt: Int
+                updatedAt: Int
+                productName: String
+            }
+            
+            type UsersList {
+                totalCount: Int!
+                users: [User!]!
+            }
+            
+            type ProductsList {
+                totalCount: Int!
+                products: [Product!]!
+            }
+            
+            type Query {
+                users: UsersList!
+                products: ProductsList!
+            }
+
+            type Mutation {
+                unused:String
+            }
+    `;
+    return buildASTSchema(parse(definition));
+}
+
+
+function expectTypesEqual(typeName:string) {
+    expect(printType(createdSchemaFromDecoratedClasses().getType(typeName)))
+        .to.eql(printType(createSchemaFromDefinition().getType(typeName)));
+}
+
+describe("building schema", () => {
+
+    describe("type Query", () => {
+        it("generates proper type", () => {
+            expectTypesEqual('Query');
+        });
+    });
+
+    describe("type User", () => {
+        it("generates proper type", () => {
+            expectTypesEqual('User');
+        });
+    });
+
+    describe("type Product", () => {
+        it("generates proper type", () => {
+            expectTypesEqual('Product');
+        });
+    });
+
+    describe("type UsersList", () => {
+        it("generates proper type", () => {
+            expectTypesEqual('UsersList');
+        });
+    });
+
+    describe("input ProductsList", () => {
+        it("generates proper type", () => {
+            expectTypesEqual('ProductsList');
+        });
+    });
+});