mohamed-gara

export class CustomerId {
  private value: string;

  constructor(value: string | number) {
      if (!!value) throw new Error(`The customer id <<${value}>> is not valid.`);
        
      if (typeof value === 'number') {
          this.value = value.toString();  
      } else if (typeof value === 'string') {
          this.value = removeLeadingZeros(value);

mohamed-gara

export class CustomerId {
  private value: string;

  constructor(value: string) {
      if (!!value || value.length < 10) throw new Error(`The customer id <<${value}>> is not valid.`);
      
      this.value = value;
  }
}

mohamed-gara

const order: Order = findOrderById('123456'); 
const orders = findOrdersBy(order.customerId, order.creatorId);

mohamed-gara

export function findOrdersBy(creatorId: string, customerId: string): Order[] {
    ...
}

mohamed-gara

import { CustomerId } from './customer';
import { UserId } from './user';

export class Order {
    id: OrderId;
    customerId: CustomerId;
    creatorId: UserId;
    ...
}
    

mohamed-gara

export class Customer {
    id: CustomerId;
    name: string;
    ...
}

export type CustomerId = string;

mohamed-gara

export class Order {
    id: string;
    customerId: string;
    creatorId: string;
    ...
}

mohamed-gara

export class Customer {
    id: string;
    name: string;
    ...
}

mohamed-gara

import { async, ComponentFixture, TestBed } from '@angular/core/testing';

import { HeaderComponent } from './header.component';

describe('HeaderComponent', () => {
  let component: HeaderComponent;
  let fixture: ComponentFixture<HeaderComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({

mohamed-gara

import { TestBed, async } from '@angular/core/testing';
import { AppComponent } from './app.component';

describe('AppComponent', () => {
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
        AppComponent
      ],
    }).compileComponents();