feat(repository): add hasManyThrough factory and tests

Co-authored-by: derdeka https://github.com/derdeka
Co-authored-by: Jam https://github.com/codejamninja

packages/repository/src/__tests__/unit/repositories/has-many-through-repository-factory.unit.ts

@@ -0,0 +1,113 @@
+// Copyright IBM Corp. 2020. All Rights Reserved.
+// Node module: @loopback/repository
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {createStubInstance, expect} from '@loopback/testlab';
+import {
+  DefaultCrudRepository,
+  Entity,
+  Getter,
+  juggler,
+  model,
+  property,
+} from '../../..';
+import {createHasManyThroughRepositoryFactory} from '../../../relations/has-many/has-many-through-repository.factory';
+import {HasManyThroughResolvedDefinition} from '../../../relations/has-many/has-many-through.helpers';
+
+describe('createHasManyThroughRepositoryFactory', () => {
+  let categoryProductLinkRepo: CategoryProductLinkRepository;
+  let productRepo: ProductRepository;
+
+  beforeEach(() => {
+    givenStubbedProductRepo();
+    givenStubbedCategoryProductLinkRepo();
+  });
+
+  it('should return a function that could create hasManyThrough repository', () => {
+    const relationMeta = resolvedMetadata as HasManyThroughResolvedDefinition;
+    const result = createHasManyThroughRepositoryFactory(
+      relationMeta,
+      Getter.fromValue(productRepo),
+      Getter.fromValue(categoryProductLinkRepo),
+    );
+    expect(result).to.be.Function();
+  });
+
+  /*------------- HELPERS ---------------*/
+
+  @model()
+  class Category extends Entity {
+    @property({id: true})
+    id: number;
+
+    constructor(data: Partial<Category>) {
+      super(data);
+    }
+  }
+
+  @model()
+  class Product extends Entity {
+    @property({id: true})
+    id: number;
+
+    constructor(data: Partial<Product>) {
+      super(data);
+    }
+  }
+
+  @model()
+  class CategoryProductLink extends Entity {
+    @property({id: true})
+    id: number;
+    @property()
+    categoryId: number;
+    @property()
+    productId: number;
+
+    constructor(data: Partial<Product>) {
+      super(data);
+    }
+  }
+
+  class ProductRepository extends DefaultCrudRepository<
+    Product,
+    typeof Product.prototype.id
+  > {
+    constructor(dataSource: juggler.DataSource) {
+      super(Product, dataSource);
+    }
+  }
+
+  class CategoryProductLinkRepository extends DefaultCrudRepository<
+    CategoryProductLink,
+    typeof CategoryProductLink.prototype.id
+  > {
+    constructor(dataSource: juggler.DataSource) {
+      super(CategoryProductLink, dataSource);
+    }
+  }
+
+  const resolvedMetadata = {
+    name: 'products',
+    type: 'hasMany',
+    targetsMany: true,
+    source: Category,
+    keyFrom: 'id',
+    target: () => Product,
+    keyTo: 'id',
+    through: {
+      model: () => CategoryProductLink,
+      keyFrom: 'categoryId',
+      keyTo: 'productId',
+    },
+  };
+
+  function givenStubbedProductRepo() {
+    productRepo = createStubInstance(ProductRepository);
+  }
+
+  function givenStubbedCategoryProductLinkRepo() {
+    categoryProductLinkRepo = createStubInstance(CategoryProductLinkRepository);
+  }
+});

packages/repository/src/relations/has-many/has-many-through-repository.factory.ts

@@ -0,0 +1,93 @@
+// Copyright IBM Corp. 2020. All Rights Reserved.
+// Node module: @loopback/repository
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {
+  DataObject,
+  Entity,
+  EntityCrudRepository,
+  Getter,
+  HasManyDefinition,
+} from '../..';
+import {
+  createTargetConstraint,
+  createThroughConstraint,
+  createThroughFkConstraint,
+  resolveHasManyThroughMetadata,
+} from './has-many-through.helpers';
+import {
+  DefaultHasManyThroughRepository,
+  HasManyThroughRepository,
+} from './has-many-through.repository';
+
+/**
+ * a factory to generate hasManyThrough repository class.
+ *
+ * Warning: The hasManyThrough interface is experimental and is subject to change.
+ * If backwards-incompatible changes are made, a new major version may not be
+ * released.
+ */
+
+export type HasManyThroughRepositoryFactory<
+  TargetEntity extends Entity,
+  TargetID,
+  ThroughEntity extends Entity,
+  ForeignKeyType
+> = (
+  fkValue: ForeignKeyType,
+) => HasManyThroughRepository<TargetEntity, TargetID, ThroughEntity>;
+
+export function createHasManyThroughRepositoryFactory<
+  Target extends Entity,
+  TargetID,
+  Through extends Entity,
+  ThroughID,
+  ForeignKeyType
+>(
+  relationMetadata: HasManyDefinition,
+  targetRepositoryGetter: Getter<EntityCrudRepository<Target, TargetID>>,
+  throughRepositoryGetter: Getter<EntityCrudRepository<Through, ThroughID>>,
+): HasManyThroughRepositoryFactory<Target, TargetID, Through, ForeignKeyType> {
+  const meta = resolveHasManyThroughMetadata(relationMetadata);
+  const result = function (fkValue: ForeignKeyType) {
+    function getTargetContraint(
+      throughInstances: Through | Through[],
+    ): DataObject<Target> {
+      return createTargetConstraint<Target, Through>(meta, throughInstances);
+    }
+    function getThroughConstraint(): DataObject<Through> {
+      const constriant: DataObject<Through> = createThroughConstraint<
+        Through,
+        ForeignKeyType
+      >(meta, fkValue);
+      return constriant;
+    }
+
+    function getThroughFkConstraint(
+      targetInstance: Target,
+    ): DataObject<Through> {
+      const constriant: DataObject<Through> = createThroughFkConstraint<
+        Target,
+        Through
+      >(meta, targetInstance);
+      return constriant;
+    }
+
+    return new DefaultHasManyThroughRepository<
+      Target,
+      TargetID,
+      EntityCrudRepository<Target, TargetID>,
+      Through,
+      ThroughID,
+      EntityCrudRepository<Through, ThroughID>
+    >(
+      targetRepositoryGetter,
+      throughRepositoryGetter,
+      getTargetContraint,
+      getThroughConstraint,
+      getThroughFkConstraint,
+    );
+  };
+  return result;
+}

packages/repository/src/relations/has-many/has-many-through.repository.ts

@@ -3,7 +3,16 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
-import {Count, DataObject, Entity, Filter, Options, Where} from '../..';
+import {
+  Count,
+  DataObject,
+  Entity,
+  EntityCrudRepository,
+  Filter,
+  Getter,
+  Options,
+  Where,
+} from '../..';
 
 /**
  * CRUD operations for a target repository of a HasManyThrough relation
@@ -28,7 +37,7 @@ export interface HasManyThroughRepository<
       throughData?: DataObject<Through>;
       throughOptions?: Options;
     },
-  ): Promise<Target>;
+  ): Promise<void>;
 
   /**
    * Find target model instance(s)
@@ -41,7 +50,7 @@ export interface HasManyThroughRepository<
     options?: Options & {
       throughOptions?: Options;
     },
-  ): Promise<Target[]>;
+  ): Promise<void>;
 
   /**
    * Delete multiple target model instances
@@ -98,3 +107,88 @@ export interface HasManyThroughRepository<
     },
   ): Promise<void>;
 }
+
+/**
+ * a class for CRUD operations for hasManyThrough relation.
+ *
+ * Warning: The hasManyThrough interface is experimental and is subject to change.
+ * If backwards-incompatible changes are made, a new major version may not be
+ * released.
+ */
+export class DefaultHasManyThroughRepository<
+  TargetEntity extends Entity,
+  TargetID,
+  TargetRepository extends EntityCrudRepository<TargetEntity, TargetID>,
+  ThroughEntity extends Entity,
+  ThroughID,
+  ThroughRepository extends EntityCrudRepository<ThroughEntity, ThroughID>
+> implements HasManyThroughRepository<TargetEntity, TargetID, ThroughEntity> {
+  constructor(
+    public getTargetRepository: Getter<TargetRepository>,
+    public getThroughRepository: Getter<ThroughRepository>,
+    public getTargetConstraint: (
+      throughInstances: ThroughEntity | ThroughEntity[],
+    ) => DataObject<TargetEntity>,
+    public getThroughConstraint: () => DataObject<ThroughEntity>,
+    public getThroughFkConstraint: (
+      targetInstance: TargetEntity,
+    ) => DataObject<ThroughEntity>,
+  ) {}
+
+  async create(
+    targetModelData: DataObject<TargetEntity>,
+    options?: Options & {
+      throughData?: DataObject<ThroughEntity>;
+      throughOptions?: Options;
+    },
+  ): Promise<void> {
+    throw new Error('Method not implemented.');
+  }
+
+  async find(
+    filter?: Filter<TargetEntity>,
+    options?: Options & {
+      throughOptions?: Options;
+    },
+  ): Promise<void> {
+    throw new Error('Method not implemented.');
+  }
+
+  async delete(
+    where?: Where<TargetEntity>,
+    options?: Options & {
+      throughOptions?: Options;
+    },
+  ): Promise<Count> {
+    throw new Error('Method not implemented.');
+  }
+
+  async patch(
+    dataObject: DataObject<TargetEntity>,
+    where?: Where<TargetEntity>,
+    options?: Options & {
+      throughOptions?: Options;
+    },
+  ): Promise<Count> {
+    throw new Error('Method not implemented.');
+  }
+
+  async link(
+    targetModelId: TargetID,
+    options?: Options & {
+      throughData?: DataObject<ThroughEntity>;
+      throughOptions?: Options;
+    },
+  ): Promise<TargetEntity> {
+    throw new Error('Method not implemented.');
+  }
+
+  async unlink(
+    targetModelId: TargetID,
+    options?: Options & {
+      throughOptions?: Options;
+    },
+  ): Promise<void> {
+    throw new Error('Method not implemented.');
+  }
+}

packages/repository/src/relations/has-many/index.ts

@@ -3,7 +3,9 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
-export * from './has-many.decorator';
-export * from './has-many.repository';
 export * from './has-many-repository.factory';
+export * from './has-many-through-repository.factory';
+export * from './has-many-through.repository';
+export * from './has-many.decorator';
 export * from './has-many.inclusion-resolver';
+export * from './has-many.repository';