feat(example-todo-list): use real relation resolvers

docs/site/tutorials/todo-list/todo-list-tutorial-repository.md

@@ -87,52 +87,24 @@ export class TodoListRepository extends DefaultCrudRepository<
 
 ### Inclusion of Related Models
 
-To get the related `Todo` objects for each `TodoList`, we can use register a
-custom
-[`InclusionResolver`](https://loopback.io/doc/en/lb4/apidocs.repository.inclusionresolver.html)
-in the `TodoList` repository.
+To get the related `Todo` objects for each `TodoList`, we can register the
+inclusion resolver that comes with the
+[`HasManyRepositoryFactory`](https://loopback.io/doc/en/lb4/apidocs.repository.hasmanyrepository.html).
+We need to register this resolver to the repository class, which we can do as
+follows:
 
-First, add the following import:
-
-```ts
-import {InclusionResolver} from '@loopback/repository';
-```
-
-Next, in the constructor, add the following custom resolver:
+{% include code-caption.html content="src/repositories/todo-list.repository.ts" %}
 
 ```ts
-export class TodoListRepository extends DefaultCrudRepository</*..*/> {
-  // ...
-  constructor(
-    //db, relation factories setup
-
-    // add the following code to build a custom resolver
-    const todosResolver: InclusionResolver<TodoList, Todo> = async todoLists => {
-      const todos: Todo[][] = [];
-      for (const todoList of todoLists) {
-        const todo = await this.todos(todoList.id).find();
-        todos.push(todo);
-      }
-
-      return todos;
-    };
-    // the resolver needs to be registered before using
-    this.registerInclusionResolver('todos', todosResolver);
-  )
-}
-```
+this.todos = this.createHasManyRepositoryFactoryFor(
+  'todos',
+  todoRepositoryGetter,
+);
 
-After that, we need to register this resolver to the repository class, which we
-can do as follows:
-
-```ts
-this.registerInclusionResolver('todos', todosResolver);
+// Add this line to register the resolver
+this.registerInclusionResolver('todos', this.todos.inclusionResolver);
 ```
 
-{% include note.html content="
-This is a temporary implementation until we implement our relation resolvers. See [GitHub issue #3450](https://github.com/strongloop/loopback-next/issues/3450) for details.
-" %}
-
 Now when you get a `TodoList`, a `todos` property will be included that contains
 your related `Todo`s, for example:
 
@@ -151,36 +123,22 @@ your related `Todo`s, for example:
 }
 ```
 
-Let's do the same on the `TodoRepository`:
+On the other end, the
+[`BelongsToAccessor`](https://loopback.io/doc/en/lb4/apidocs.repository.belongstoaccessor.html)
+also comes with an inclusion resolver property that we can register on the
+`TodoRepository`. So, let's register this resolver to the `TodoRepository`
+similar to how we did it for the `TodoListRepository`:
 
 {% include code-caption.html content="src/repositories/todo.repository.ts" %}
 
 ```ts
-// .. other imports
-import {InclusionResolver} from '@loopback/repository';
-```
-
-```ts
-export class TodoRepository extends DefaultCrudRepository</*..*/> {
-  // ...
-  constructor(
-    //db, factories setup
+this.todoList = this.createBelongsToAccessorFor(
+  'todoList',
+  todoListRepositoryGetter,
+);
 
-    // add the following code to build/register a custom resolver
-    const todoListResolver: InclusionResolver<Todo, TodoList> = async todos => {
-      const todoLists = [];
-
-      for (const todo of todos) {
-        const todoList = await this.todoList(todo.id);
-        todoLists.push(todoList);
-      }
-
-      return todoLists;
-    };
-
-    this.registerInclusionResolver('todoList', todoListResolver);
-  )
-}
+// Add this line to register the resolver
+this.registerInclusionResolver('todoList', this.todoList.inclusionResolver);
 ```
 
 We're now ready to expose `TodoList` and its related `Todo` API through the

examples/todo-list/src/__tests__/integration/todo-list-image.repository.integration.ts

@@ -63,4 +63,20 @@ describe('TodoListImageRepository', () => {
       todoList: toJSON(list),
     });
   });
+
+  it('includes TodoList in findOne result', async () => {
+    const list = await givenTodoListInstance(todoListRepo, {});
+    const image = await givenTodoListImageInstance(todoListImageRepo, {
+      todoListId: list.id,
+    });
+
+    const response = await todoListImageRepo.findOne({
+      include: [{relation: 'todoList'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual({
+      ...toJSON(image),
+      todoList: toJSON(list),
+    });
+  });
 });

examples/todo-list/src/__tests__/integration/todo-list.repository.integration.ts

@@ -7,6 +7,7 @@ import {
 import {
   givenEmptyDatabase,
   givenTodoInstance,
+  givenTodoListImageInstance,
   givenTodoListInstance,
   testdb,
 } from '../helpers';
@@ -23,6 +24,10 @@ describe('TodoListRepository', () => {
       async () => todoListImageRepo,
     );
     todoRepo = new TodoRepository(testdb, async () => todoListRepo);
+    todoListImageRepo = new TodoListImageRepository(
+      testdb,
+      async () => todoListRepo,
+    );
   });
 
   beforeEach(givenEmptyDatabase);
@@ -56,4 +61,89 @@ describe('TodoListRepository', () => {
       todos: [toJSON(todo)],
     });
   });
+
+  it('includes Todos in findOne method result', async () => {
+    const list = await givenTodoListInstance(todoListRepo);
+    const todo = await givenTodoInstance(todoRepo, {todoListId: list.id});
+
+    const response = await todoListRepo.findOne({
+      where: {id: list.id},
+      include: [{relation: 'todos'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual({
+      ...toJSON(list),
+      todos: [toJSON(todo)],
+    });
+  });
+
+  it('includes TodoListImage in find method result', async () => {
+    const list = await givenTodoListInstance(todoListRepo);
+    const image = await givenTodoListImageInstance(todoListImageRepo, {
+      todoListId: list.id,
+    });
+
+    const response = await todoListRepo.find({
+      include: [{relation: 'image'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual([
+      {
+        ...toJSON(list),
+        image: toJSON(image),
+      },
+    ]);
+  });
+
+  it('includes TodoListImage in findById method result', async () => {
+    const list = await givenTodoListInstance(todoListRepo);
+    const image = await givenTodoListImageInstance(todoListImageRepo, {
+      todoListId: list.id,
+    });
+
+    const response = await todoListRepo.findById(list.id, {
+      include: [{relation: 'image'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual({
+      ...toJSON(list),
+      image: toJSON(image),
+    });
+  });
+
+  it('includes TodoListImage in findOne method result', async () => {
+    const list = await givenTodoListInstance(todoListRepo);
+    const image = await givenTodoListImageInstance(todoListImageRepo, {
+      todoListId: list.id,
+    });
+
+    const response = await todoListRepo.findOne({
+      include: [{relation: 'image'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual({
+      ...toJSON(list),
+      image: toJSON(image),
+    });
+  });
+
+  it('includes both Todos and TodoListImage in find method result', async () => {
+    const list = await givenTodoListInstance(todoListRepo);
+    const todo = await givenTodoInstance(todoRepo, {todoListId: list.id});
+    const image = await givenTodoListImageInstance(todoListImageRepo, {
+      todoListId: list.id,
+    });
+
+    const response = await todoListRepo.find({
+      include: [{relation: 'image'}, {relation: 'todos'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual([
+      {
+        ...toJSON(list),
+        image: toJSON(image),
+        todos: [toJSON(todo)],
+      },
+    ]);
+  });
 });

examples/todo-list/src/__tests__/integration/todo.repository.integration.ts

@@ -56,4 +56,18 @@ describe('TodoRepository', () => {
       todoList: toJSON(list),
     });
   });
+
+  it('includes TodoList in findOne method result', async () => {
+    const list = await givenTodoListInstance(todoListRepo);
+    const todo = await givenTodoInstance(todoRepo, {todoListId: list.id});
+
+    const response = await todoRepo.findOne({
+      include: [{relation: 'todoList'}],
+    });
+
+    expect(toJSON(response)).to.deepEqual({
+      ...toJSON(todo),
+      todoList: toJSON(list),
+    });
+  });
 });

examples/todo-list/src/repositories/todo-list-image.repository.ts

@@ -7,7 +7,6 @@ import {Getter, inject} from '@loopback/core';
 import {
   BelongsToAccessor,
   DefaultCrudRepository,
-  InclusionResolver,
   repository,
 } from '@loopback/repository';
 import {DbDataSource} from '../datasources';
@@ -29,27 +28,12 @@ export class TodoListImageRepository extends DefaultCrudRepository<
     protected todoListRepositoryGetter: Getter<TodoListRepository>,
   ) {
     super(TodoListImage, dataSource);
+
     this.todoList = this.createBelongsToAccessorFor(
       'todoList',
       todoListRepositoryGetter,
     );
 
-    // this is a temporary implementation until
-    // https://github.com/strongloop/loopback-next/issues/3450 is landed
-    const todoListResolver: InclusionResolver<
-      TodoListImage,
-      TodoList
-    > = async images => {
-      const todoLists = [];
-
-      for (const image of images) {
-        const todoList = await this.todoList(image.id);
-        todoLists.push(todoList);
-      }
-
-      return todoLists;
-    };
-
-    this.registerInclusionResolver('todoList', todoListResolver);
+    this.registerInclusionResolver('todoList', this.todoList.inclusionResolver);
   }
 }

examples/todo-list/src/repositories/todo-list.repository.ts

@@ -8,7 +8,6 @@ import {
   DefaultCrudRepository,
   HasManyRepositoryFactory,
   HasOneRepositoryFactory,
-  InclusionResolver,
   juggler,
   repository,
 } from '@loopback/repository';
@@ -38,50 +37,20 @@ export class TodoListRepository extends DefaultCrudRepository<
     protected todoListImageRepositoryGetter: Getter<TodoListImageRepository>,
   ) {
     super(TodoList, dataSource);
+
     this.todos = this.createHasManyRepositoryFactoryFor(
       'todos',
       todoRepositoryGetter,
     );
 
-    // this is a temporary implementation until
-    // https://github.com/strongloop/loopback-next/issues/3450 is landed
-    const todosResolver: InclusionResolver<
-      TodoList,
-      Todo
-    > = async todoLists => {
-      const todos: Todo[][] = [];
-      for (const todoList of todoLists) {
-        const todo = await this.todos(todoList.id).find();
-        todos.push(todo);
-      }
-
-      return todos;
-    };
-
-    this.registerInclusionResolver('todos', todosResolver);
+    this.registerInclusionResolver('todos', this.todos.inclusionResolver);
 
     this.image = this.createHasOneRepositoryFactoryFor(
       'image',
       todoListImageRepositoryGetter,
     );
 
-    // this is a temporary implementation until
-    // https://github.com/strongloop/loopback-next/issues/3450 is landed
-    const imageResolver: InclusionResolver<
-      TodoList,
-      TodoListImage
-    > = async todoLists => {
-      const images = [];
-
-      for (const todoList of todoLists) {
-        const image = await this.image(todoList.id).get();
-        images.push(image);
-      }
-
-      return images;
-    };
-
-    this.registerInclusionResolver('image', imageResolver);
+    this.registerInclusionResolver('image', this.image.inclusionResolver);
   }
 
   public findByTitle(title: string) {

examples/todo-list/src/repositories/todo.repository.ts

@@ -7,7 +7,6 @@ import {Getter, inject} from '@loopback/core';
 import {
   BelongsToAccessor,
   DefaultCrudRepository,
-  InclusionResolver,
   juggler,
   repository,
 } from '@loopback/repository';
@@ -35,20 +34,6 @@ export class TodoRepository extends DefaultCrudRepository<
       'todoList',
       todoListRepositoryGetter,
     );
-
-    // this is a temporary implementation until
-    // https://github.com/strongloop/loopback-next/issues/3450 is landed
-    const todoListResolver: InclusionResolver<Todo, TodoList> = async todos => {
-      const todoLists = [];
-
-      for (const todo of todos) {
-        const todoList = await this.todoList(todo.id);
-        todoLists.push(todoList);
-      }
-
-      return todoLists;
-    };
-
-    this.registerInclusionResolver('todoList', todoListResolver);
+    this.registerInclusionResolver('todoList', this.todoList.inclusionResolver);
   }
 }