typescript-constructor.ts

export class Person {
  private id: number;
  private firstName: string;
  private address: string;

  constructor(id: number, firstName: string, address: string) {
    this.id = id;
    this.firstName = firstName;
    this.address = address;
  }
  
  showValues() {
    console.log(this.number);
    console.log(this.firstName);
    console.log(this.address);
  }
}

// Using access modifiers in constructor
// There's no need to declare attributes into the class.
export class Person {
  constructor(private id: number, private firstName: string, private address: string) {}
  
  showValues() {
    console.log(this.number);
    console.log(this.firstName);
    console.log(this.address);
  }
}