feat(repository): implement EntityNotFoundError

Author: bajtos

packages/repository/src/errors/entity-not-found.error.ts

@@ -0,0 +1,40 @@
+// Copyright IBM Corp. 2018. 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 {Entity} from '../model';
+
+export class EntityNotFoundError<ID, Props extends object = {}> extends Error {
+  code: string;
+  entityName: string;
+  entityId: ID;
+
+  constructor(
+    entityOrName: typeof Entity | string,
+    entityId: ID,
+    extraProperties?: Props,
+  ) {
+    const entityName =
+      typeof entityOrName === 'string'
+        ? entityOrName
+        : entityOrName.modelName || entityOrName.name;
+
+    const quotedId = JSON.stringify(entityId);
+
+    super(`Entity not found: ${entityName} with id ${quotedId}`);
+
+    Error.captureStackTrace(this, this.constructor);
+
+    this.code = 'ENTITY_NOT_FOUND';
+    this.entityName = entityName;
+    this.entityId = entityId;
+
+    Object.assign(this, extraProperties);
+  }
+}
+
+// tslint:disable-next-line:no-any
+export function isEntityNotFoundError(e: any): e is EntityNotFoundError<any> {
+  return e instanceof EntityNotFoundError;
+}

packages/repository/src/errors/index.ts

@@ -0,0 +1,6 @@
+// Copyright IBM Corp. 2018. All Rights Reserved.
+// Node module: @loopback/repository
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+export * from './entity-not-found.error';

packages/repository/src/index.ts

@@ -5,6 +5,7 @@
 
 export * from './connectors';
 export * from './decorators';
+export * from './errors';
 export * from './mixins';
 export * from './repositories';
 export * from './types';

packages/repository/test/unit/errors/entity-not-found-error.test.ts

@@ -0,0 +1,72 @@
+// Copyright IBM Corp. 2017,2018. 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 {expect} from '@loopback/testlab';
+import {
+  Entity,
+  EntityNotFoundError,
+  model,
+  isEntityNotFoundError,
+} from '../../../';
+
+describe('EntityNotFoundError', () => {
+  it('inherits from Error correctly', () => {
+    const err = givenAnErrorInstance();
+    expect(err).to.be.instanceof(EntityNotFoundError);
+    expect(err).to.be.instanceof(Error);
+    expect(err.stack)
+      .to.be.String()
+      .and.match((s: string) => s.indexOf(__filename) > -1);
+  });
+
+  it('sets code to "ENTITY_NOT_FOUND"', () => {
+    const err = givenAnErrorInstance();
+    expect(err.code).to.equal('ENTITY_NOT_FOUND');
+  });
+
+  it('sets entity name and id properties', () => {
+    const err = new EntityNotFoundError('Product', 'an-id');
+    expect(err).to.have.properties({
+      entityName: 'Product',
+      entityId: 'an-id',
+    });
+  });
+
+  it('has a descriptive error message', () => {
+    const err = new EntityNotFoundError('Product', 'an-id');
+    expect(err.message).to.match(/not found.*Product.*"an-id"/);
+  });
+
+  it('infers entity name from entity class via name', () => {
+    class Product extends Entity {}
+
+    const err = new EntityNotFoundError(Product, 1);
+    expect(err.entityName).to.equal('Product');
+  });
+
+  it('infers entity name from entity class via modelName', () => {
+    @model({name: 'CustomProduct'})
+    class Product extends Entity {}
+
+    const err = new EntityNotFoundError(Product, 1);
+    expect(err.entityName).to.equal('CustomProduct');
+  });
+
+  function givenAnErrorInstance() {
+    return new EntityNotFoundError('Product', 1);
+  }
+});
+
+describe('isEntityNotFoundError', () => {
+  it('returns true for an instance of EntityNotFoundError', () => {
+    const error = new EntityNotFoundError('Product', 123);
+    expect(isEntityNotFoundError(error)).to.be.true();
+  });
+
+  it('returns false for an instance of Error', () => {
+    const error = new Error('A generic error');
+    expect(isEntityNotFoundError(error)).to.be.false();
+  });
+});