Dealing with circular references in class attributes within Angular

I'm facing a challenge in Angular while trying to set up mock data. I have the following two classes:

export class Company {

  public id: number;
  public name: string;
  public applications: Application[];

  constructor(id: number, name: string, applications: Application[]) {
    this.id = id;
    this.name = name;
    this.applications = applications;
  }
}

export class Application {

  public id: number;
  public name: string;
  public company: Company;

  constructor(id: number, name: string, company: Company) {
    this.id = id;
    this.name = name;
    this.company = company;
  }
}

I've also created these services:

export class CompanyService {

  companies = [
    new Company(
      1,
      'Company 1',
      []
    ),
    new Company(
      2,
      'Company 2',
      [],
    ),
  ]

  constructor(private http: HttpClient) { }

  getAll(): Company[] {
    return this.companies;
  }

  findById(id: number): Company | undefined {
    return this.companies.find(company => company.id === id);
  }
}



export class ApplicationService {

  applications = [
    new Application(
      1,
      'Application 1',
      // COMPANY HERE SOMEHOW?
    ),
    new Application(
      2,
      'Application 2',
      // COMPANY HERE SOMEHOW?
    ),
  ]

  constructor(private http: HttpClient) { }

  getAll(): Application[] {
    return this.applications;
  }

  findById(id: number): Application | undefined {
    return this.applications.find(application => application.id === id);
  }
}

Now, the issue arises when creating this mock data because I need to add a company to the constructor of an application. However, adding a company there requires that the object contain the application in its constructor as well. This creates a chicken/egg problem, and I am unsure how to resolve it.

Being new to Angular, I'm not sure if there's a workaround within the framework itself or if I should use IDs of the classes. Even with using IDs, I still face the same dilemma. Can anyone provide guidance on this matter?

Answer №1

Think of it this way: a company can exist without applications, but an application typically needs a company to be created.

Start by creating companies, then use those companies to create applications and add them to the company's application list during creation.

Consider if you really need to list applications under companies - perhaps you could search for applications based on the company instead.

This is more about data modeling than Angular, especially when working in a simulated environment that differs from real-world scenarios where companies precede the creation of applications.

To "fix" this issue, consider separating the data creation process. Create the data independently, possibly in a data service, and then query it from your services for a more realistic approach.

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