Add support for typeDefs and resolvers ecosystem compatibility

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Features
 - **Breaking Change**: change the default `PrintSchemaOptions` option `commentDescriptions` to false (no more `#` comments in SDL)
 - add support for passing `PrintSchemaOptions` in `buildSchema.emitSchemaFile` (e.g. `commentDescriptions: true` to restore previous behavior)
+- add `buildTypeDefsAndResolvers` utils function for generating apollo-like `typeDefs` and `resolvers` pair (#233)
 
 ## v0.16.0
 ### Features

docs/bootstrap.md

@@ -78,3 +78,37 @@ bootstrap();
 Remember to install `apollo-server` package from npm - it's not bundled with TypeGraphQL.
 
 Of course you can use `express-graphql` middleware, `graphql-yoga` or whatever you want 😉
+
+## Create typeDefs and resolvers map
+
+TypeGraphQL also provides a second way to generate the GraphQL schema - the `buildTypeDefsAndResolvers` function.
+
+It accepts the same `BuildSchemaOptions` like the `buildSchema` function but instead of an executable `GraphQLSchema`, it creates a typeDefs and resolversMap pair that you can use e.g. with [`graphql-tools`](https://github.com/apollographql/graphql-tools):
+```typescript
+import { makeExecutableSchema } from "graphql-tools";
+
+const { typeDefs, resolvers } = await buildTypeDefsAndResolvers({
+  resolvers: [FirstResolver, SecondResolver],
+});
+
+const schema = makeExecutableSchema({ typeDefs, resolvers });
+```
+
+Or even with other libraries that expect the schema info in that shape, like [`apollo-link-state`](https://github.com/apollographql/apollo-link-state):
+```typescript
+import { withClientState } from 'apollo-link-state';
+
+const { typeDefs, resolvers } = await buildTypeDefsAndResolvers({
+  resolvers: [FirstResolver, SecondResolver],
+});
+
+const stateLink = withClientState({
+  // ...other options like `cache`
+  typeDefs,
+  resolvers,
+});
+
+// ...the rest of `ApolloClient` initialization code
+```
+
+Be aware that some of the TypeGraphQL features (i.a. [query complexity](complexity.md)) might not work with `buildTypeDefsAndResolvers` approach because they use some low-level `graphql-js` features.

src/index.ts

@@ -2,17 +2,6 @@ export * from "./decorators";
 export * from "./scalars";
 export * from "./errors";
 export * from "./interfaces";
-
-export { buildSchema, buildSchemaSync, BuildSchemaOptions } from "./utils/buildSchema";
-export {
-  emitSchemaDefinitionFile,
-  emitSchemaDefinitionFileSync,
-} from "./utils/emitSchemaDefinitionFile";
-export {
-  useContainer,
-  ContainerType,
-  ContainerGetter,
-  UseContainerOptions,
-} from "./utils/container";
+export * from "./utils";
 
 export { PubSubEngine } from "graphql-subscriptions";

src/interfaces/index.ts

@@ -5,5 +5,6 @@ export * from "./Complexity";
 export * from "./Publisher";
 export * from "./ResolverData";
 export * from "./ResolverFilterData";
-export * from "./ResolverTopicData";
 export * from "./ResolverInterface";
+export * from "./resolvers-map";
+export * from "./ResolverTopicData";

src/interfaces/resolvers-map.ts

@@ -0,0 +1,30 @@
+import {
+  GraphQLScalarType,
+  GraphQLFieldResolver,
+  GraphQLTypeResolver,
+  GraphQLIsTypeOfFn,
+} from "graphql";
+
+export interface ResolversMap<TSource = any, TContext = any> {
+  [key: string]:
+    | ResolverObject<TSource, TContext>
+    | ResolverOptions<TSource, TContext>
+    | GraphQLScalarType
+    | EnumResolver;
+}
+
+export interface ResolverObject<TSource = any, TContext = any> {
+  [key: string]: ResolverOptions<TSource, TContext>;
+}
+
+export interface EnumResolver {
+  [key: string]: string | number;
+}
+
+export interface ResolverOptions<TSource = any, TContext = any> {
+  fragment?: string;
+  resolve?: GraphQLFieldResolver<TSource, TContext>;
+  subscribe?: GraphQLFieldResolver<TSource, TContext>;
+  __resolveType?: GraphQLTypeResolver<TSource, TContext>;
+  __isTypeOf?: GraphQLIsTypeOfFn<TSource, TContext>;
+}

src/utils/buildTypeDefsAndResolvers.ts

@@ -0,0 +1,11 @@
+import { printSchema } from "graphql";
+
+import { BuildSchemaOptions, buildSchema } from "./buildSchema";
+import { createResolversMap } from "./createResolversMap";
+
+export async function buildTypeDefsAndResolvers(options: BuildSchemaOptions) {
+  const schema = await buildSchema(options);
+  const typeDefs = printSchema(schema);
+  const resolvers = createResolversMap(schema);
+  return { typeDefs, resolvers };
+}

src/utils/createResolversMap.ts

@@ -0,0 +1,86 @@
+import {
+  GraphQLScalarType,
+  GraphQLEnumType,
+  GraphQLObjectType,
+  GraphQLInterfaceType,
+  GraphQLUnionType,
+  GraphQLFieldMap,
+  GraphQLSchema,
+  GraphQLTypeResolver,
+  GraphQLAbstractType,
+} from "graphql";
+
+import { ResolversMap, EnumResolver, ResolverObject } from "../interfaces";
+
+export function createResolversMap(schema: GraphQLSchema): ResolversMap {
+  const typeMap = schema.getTypeMap();
+  return Object.keys(typeMap)
+    .filter(typeName => !typeName.includes("__"))
+    .reduce<ResolversMap>((resolversMap, typeName) => {
+      const type = typeMap[typeName];
+      if (type instanceof GraphQLObjectType) {
+        resolversMap[typeName] = {
+          __isTypeOf: type.isTypeOf || undefined,
+          ...generateFieldsResolvers(type.getFields()),
+        };
+      }
+      if (type instanceof GraphQLInterfaceType) {
+        resolversMap[typeName] = {
+          __resolveType: generateTypeResolver(type, schema),
+          ...generateFieldsResolvers(type.getFields()),
+        };
+      }
+      if (type instanceof GraphQLScalarType) {
+        resolversMap[typeName] = type;
+      }
+      if (type instanceof GraphQLEnumType) {
+        const enumValues = type.getValues();
+        resolversMap[typeName] = enumValues.reduce<EnumResolver>((enumMap, { name, value }) => {
+          enumMap[name] = value;
+          return enumMap;
+        }, {});
+      }
+      if (type instanceof GraphQLUnionType) {
+        resolversMap[typeName] = {
+          __resolveType: generateTypeResolver(type, schema),
+        };
+      }
+      return resolversMap;
+    }, {});
+}
+
+function generateTypeResolver(
+  abstractType: GraphQLAbstractType,
+  schema: GraphQLSchema,
+): GraphQLTypeResolver<any, any> {
+  if (abstractType.resolveType) {
+    return async (source, context, info) => {
+      const detectedType = await abstractType.resolveType!(source, context, info);
+      if (detectedType instanceof GraphQLObjectType) {
+        return detectedType.name;
+      }
+      return detectedType;
+    };
+  }
+
+  const possibleObjectTypes = schema.getPossibleTypes(abstractType);
+  return async (source, context, info) => {
+    for (const objectType of possibleObjectTypes) {
+      if (objectType.isTypeOf && (await objectType.isTypeOf(source, context, info))) {
+        return objectType.name;
+      }
+    }
+    return null;
+  };
+}
+
+function generateFieldsResolvers(fields: GraphQLFieldMap<any, any>): ResolverObject {
+  return Object.keys(fields).reduce<ResolverObject>((fieldsMap, fieldName) => {
+    const field = fields[fieldName];
+    fieldsMap[fieldName] = {
+      subscribe: field.subscribe,
+      resolve: field.resolve,
+    };
+    return fieldsMap;
+  }, {});
+}

src/utils/index.ts

@@ -0,0 +1,4 @@
+export { buildSchema, buildSchemaSync, BuildSchemaOptions } from "./buildSchema";
+export { buildTypeDefsAndResolvers } from "./buildTypeDefsAndResolvers";
+export { emitSchemaDefinitionFile, emitSchemaDefinitionFileSync } from "./emitSchemaDefinitionFile";
+export { useContainer, ContainerType, ContainerGetter, UseContainerOptions } from "./container";