Refactoring to UUIDs

package.json

@@ -27,6 +27,7 @@
     "@types/helmet": "0.0.44",
     "@types/node": "~13.1.1",
     "@types/uuid": "^3.4.6",
+    "@types/uuid-validate": "0.0.1",
     "body-parser": "^1.19.0",
     "bson": "^4.0.2",
     "compression": "^1.7.4",
@@ -42,6 +43,7 @@
     "ts-node": "^8.3.0",
     "typescript": "^3.4.5",
     "uuid": "^3.3.3",
+    "uuid-validate": "0.0.3",
     "winston": "^3.2.1"
   },
   "devDependencies": {

src/Contexts/Mooc/Courses/application/CourseCreator.ts

@@ -1,6 +1,7 @@
 import { CourseRepository } from '../domain/CourseRepository';
 import { Course } from '../domain/Course';
 import { CreateCourseRequest } from './CreateCourseRequest';
+import { CourseId } from '../../Shared/domain/Courses/CourseId';
 
 export class CourseCreator {
   private repository: CourseRepository;
@@ -10,7 +11,7 @@ export class CourseCreator {
   }
 
   async run(request: CreateCourseRequest): Promise<void> {
-    const course = new Course(request.id, request.name, request.duration);
+    const course = new Course(new CourseId(request.id), request.name, request.duration);
 
     return this.repository.save(course);
   }

src/Contexts/Mooc/Courses/domain/Course.ts

@@ -1,9 +1,11 @@
+import { CourseId } from '../../Shared/domain/Courses/CourseId';
+
 export class Course {
-  readonly id: string;
+  readonly id: CourseId;
   readonly name: string;
   readonly duration: string;
 
-  constructor(id: string, name: string, duration: string) {
+  constructor(id: CourseId, name: string, duration: string) {
     this.id = id;
     this.name = name;
     this.duration = duration;

src/Contexts/Mooc/Courses/domain/CourseRepository.ts

@@ -1,8 +1,9 @@
 import { Nullable } from '../../../Shared/domain/Nullable';
 import { Course } from './Course';
+import { CourseId } from '../../Shared/domain/Courses/CourseId';
 
 export interface CourseRepository {
   save(course: Course): Promise<void>;
 
-  search(id: string): Promise<Nullable<Course>>;
+  search(id: CourseId): Promise<Nullable<Course>>;
 }

src/Contexts/Mooc/Courses/infrastructure/FileCourseRepository.ts

@@ -3,22 +3,23 @@ import { Course } from '../domain/Course';
 import fs from 'fs';
 import BSON from 'bson';
 import { Nullable } from '../../../Shared/domain/Nullable';
+import { CourseId } from '../../Shared/domain/Courses/CourseId';
 
 export class FileCourseRepository implements CourseRepository {
   private FILE_PATH = `${__dirname}/courses`;
 
   async save(course: Course): Promise<void> {
-    const filePath = this.filePath(course.id);
+    const filePath = this.filePath(course.id.value);
     const data = BSON.serialize(course);
 
     return fs.writeFileSync(filePath, data);
   }
 
-  async search(id: string): Promise<Nullable<Course>> {
-    const filePath = this.filePath(id);
+  async search(id: CourseId): Promise<Nullable<Course>> {
+    const filePath = this.filePath(id.value);
     const exists = fs.existsSync(filePath);
 
-    return exists ? BSON.deserialize(fs.readFileSync(this.filePath(id))) : null;
+    return exists ? BSON.deserialize(fs.readFileSync(this.filePath(id.value))) : null;
   }
 
   private filePath(id: string): string {

src/Contexts/Mooc/Shared/domain/Courses/CourseId.ts

@@ -0,0 +1,3 @@
+import { Uuid } from '../../../../Shared/domain/value-object/Uuid';
+
+export class CourseId extends Uuid {}

src/Contexts/Shared/domain/value-object/InvalidArgumentError.ts

@@ -0,0 +1 @@
+export class InvalidArgumentError extends Error {}

src/Contexts/Shared/domain/value-object/Uuid.ts

@@ -0,0 +1,27 @@
+import uuid from 'uuid/v4';
+import validate from 'uuid-validate';
+import { InvalidArgumentError } from './InvalidArgumentError';
+
+export class Uuid {
+  readonly value: string;
+
+  constructor(value: string) {
+    this.ensureIsValidUuid(value);
+
+    this.value = value;
+  }
+
+  static random(): Uuid {
+    return new Uuid(uuid());
+  }
+
+  private ensureIsValidUuid(id: string): void {
+    if (!validate(id)) {
+      throw new InvalidArgumentError(`<${this.constructor.name}> does not allow the value <${id}>`);
+    }
+  }
+
+  toString(): string {
+    return this.value;
+  }
+}

tests/Contexts/Mooc/Courses/application/CourseCreator.test.ts

@@ -1,6 +1,7 @@
 import { Course } from '../../../../../src/Contexts/Mooc/Courses/domain/Course';
 import { CourseCreator } from '../../../../../src/Contexts/Mooc/Courses/application/CourseCreator';
 import { CourseRepository } from '../../../../../src/Contexts/Mooc/Courses/domain/CourseRepository';
+import { CourseId } from '../../../../../src/Contexts/Mooc/Shared/domain/Courses/CourseId';
 
 describe('Course Creator', () => {
   it('should create a valid course', async () => {
@@ -12,11 +13,11 @@ describe('Course Creator', () => {
 
     const createCourse = new CourseCreator(repository);
 
-    const id = 'some-id';
+    const id = '0766c602-d4d4-48b6-9d50-d3253123275e';
     const name = 'some-name';
     const duration = 'some-duration';
 
-    const course = new Course(id, name, duration);
+    const course = new Course(new CourseId(id), name, duration);
 
     await createCourse.run({ id, name, duration });
 

tests/Contexts/Mooc/Courses/infrastructure/FileCourseRepository.test.ts

@@ -1,10 +1,11 @@
 import { FileCourseRepository } from '../../../../../src/Contexts/Mooc/Courses/infrastructure/FileCourseRepository';
 import { Course } from '../../../../../src/Contexts/Mooc/Courses/domain/Course';
+import { CourseId } from '../../../../../src/Contexts/Mooc/Shared/domain/Courses/CourseId';
 
 describe('Save Course', () => {
   it('should have a course', () => {
     const repository = new FileCourseRepository();
-    const course = new Course('id', 'name', 'duration');
+    const course = new Course(new CourseId('0766c602-d4d4-48b6-9d50-d3253123275e'), 'name', 'duration');
 
     repository.save(course);
   });