feature(modules): add .forRootAsync() support (#8)

Co-authored-by: Michał Lytek <michal.wojciech.lytek@gmail.com>

Author: clayrisser

README.md

@@ -25,9 +25,11 @@ npm i type-graphql
 
 ## How to use?
 
-The `typegraphql-nestjs` package exports `TypeGraphQLModule` dynamic module, which is based on the official NestJS `GraphQLModule`.
+The `typegraphql-nestjs` package exports `TypeGraphQLModule` dynamic module, which is based on the official NestJS `GraphQLModule`. It exposes three static methods:
 
-It exposes two static methods. The first one is `TypeGraphQLModule.forRoot()` which you should call on your root module, just like with `GraphQLModule`.
+### `.forRoot()`
+
+The first one is `TypeGraphQLModule.forRoot()` which you should call on your root module, just like with the official `GraphQLModule`.
 
 The only difference is that as its argument you can provide [typical TypeGraphQL `buildSchema` options](https://typegraphql.com/docs/bootstrap.html) like `emitSchemaFile` or `authChecker` apart from the [standard `GqlModuleOptions` from `@nestjs/graphql`](https://docs.nestjs.com/graphql/quick-start#installation) like `installSubscriptionHandlers` or `context`:
 
@@ -71,6 +73,8 @@ And that's it! 😁
 
 Notice that the resolvers classes are automatically inferred from your submodules `providers` array, so you don't need to specify `resolvers` property from TypeGraphQL `buildSchema` options inside `TypeGraphQLModule.forRoot()`.
 
+### `.forFeature()`
+
 In case of need to provide `orphanedTypes` setting, you should use `TypeGraphQLModule.forFeature()`. The recommended place for that is in the module where the orphaned type (like `SuperRecipe`) belongs:
 
 ```ts
@@ -94,6 +98,34 @@ export default class RecipeModule {}
 
 Using `.forFeature()` ensures proper schemas isolation and automatically supply `orphanedTypes` option for underlying `buildSchema` from TypeGraphQL - again, there's no need to provide it manually in `.forRoot()` options.
 
+### `.forRootAsync()`
+
+If you need to access some services to construct the `TypeGraphQLModule` options, you might be interested in the `TypeGraphQLModule.forRootAsync()` method. It allows you to define your own `useFactory` implementation where you have injected services from `imports` option.
+
+Example of using the config service to generate `TypeGraphQLModule` options:
+
+```ts
+@Module({
+  imports: [
+    ConfigModule,
+    RecipeModule,
+    TypeGraphQLModule.forRootAsync({
+      inject: [ConfigService],
+      useFactory: async (config: ConfigService) => ({
+        cors: true,
+        debug: config.isDevelopmentMode,
+        playground: !config.isDevelopmentMode,
+        validate: false,
+        dateScalarMode: "timestamp",
+        emitSchemaFile:
+          config.isDevelopmentMode && path.resolve(__dirname, "schema.gql"),
+      }),
+    }),
+  ],
+})
+export default class AppModule {}
+```
+
 ## Caveats
 
 While this integration provides a way to use TypeGraphQL with NestJS modules and dependency injector, for now it doesn't support [other NestJS features](https://docs.nestjs.com/graphql/tooling) like guards, interceptors, filters and pipes.

src/typegraphql.module.ts

@@ -9,6 +9,7 @@ import TypeGraphQLOptionsFactory from "./typegraphql-options.factory";
 import {
   TypeGraphQLFeatureModuleOptions,
   TypeGraphQLRootModuleOptions,
+  TypeGraphQLRootModuleAsyncOptions,
 } from "./types";
 
 @Module({})
@@ -42,4 +43,23 @@ export class TypeGraphQLModule {
       ],
     };
   }
+
+  static forRootAsync(
+    asyncOptions: TypeGraphQLRootModuleAsyncOptions,
+  ): DynamicModule {
+    const dynamicGraphQLModule = GraphQLModule.forRootAsync({
+      useClass: TypeGraphQLOptionsFactory,
+    });
+    return {
+      ...dynamicGraphQLModule,
+      providers: [
+        ...dynamicGraphQLModule.providers!,
+        {
+          inject: asyncOptions.inject,
+          provide: TYPEGRAPHQL_ROOT_MODULE_OPTIONS,
+          useFactory: asyncOptions.useFactory,
+        },
+      ],
+    };
+  }
 }

src/types.ts

@@ -1,5 +1,6 @@
-import { GqlModuleOptions } from "@nestjs/graphql";
 import { BuildSchemaOptions } from "type-graphql";
+import { GqlModuleOptions } from "@nestjs/graphql";
+import { FactoryProvider, ModuleMetadata } from "@nestjs/common/interfaces";
 
 export type TypeGraphQLFeatureModuleOptions = Pick<
   BuildSchemaOptions,
@@ -11,3 +12,12 @@ export type TypeGraphQLRootModuleOptions = Omit<
   "schema" | "autoSchemaFile" | "buildSchemaOptions"
 > &
   Omit<BuildSchemaOptions, "resolvers" | "orphanedTypes" | "container">;
+
+export interface TypeGraphQLRootModuleAsyncOptions
+  extends Pick<ModuleMetadata, "imports">,
+    Pick<
+      FactoryProvider<
+        Promise<TypeGraphQLRootModuleOptions> | TypeGraphQLRootModuleOptions
+      >,
+      "inject" | "useFactory"
+    > {}