Typescript class getters are not returning any data-CodePudding

I am trying to create a Typescript class that has read-only properties based on other properties in the class. The properties in question are the firstLastName and lastFirstName properties. Here is my class:

export interface IMember {
  id: string;
  firstName: string;
  lastName: string;
  active: boolean;
  readonly firstLastName: string;
  readonly lastFirstName: string;
}

export class Member implements IMember {
  id: string;
  firstName: string;
  lastName: string;
  active: boolean;
  get firstLastName(): string {
    return `${this.firstName} ${this.lastName}`;
  }
  get lastFirstName(): string {
    return `${this.lastName}, ${this.firstName}`;
  }
}

I have tried manually creating a new member object and assigning the four required properties, and I also tried creating member objects from JSON. In both cases, the code acts like the firstLastName and lastFirstName properties aren't there at all. Also, when creating the object manually, I have to mark the type as Partial, or the compiler complains that the object is missing properties (firstLastName and lastFirstName). This seems so straightforward, and I found another question here that basically showed exactly what I'm doing as the solution, but it's just not working for me.

CodePudding user response：

Mb You have to initialize properties. This code works in the playground:

interface IMember {
  id: string;
  firstName: string;
  lastName: string;
  active: boolean;
  readonly firstLastName: string;
  readonly lastFirstName: string;
}

class Member implements IMember {
  id: string = "";
  firstName: string = "first";
  lastName: string = "last";
  active: boolean = false;
  get firstLastName(): string {
    return `${this.firstName} ${this.lastName}`;
  }
  get lastFirstName(): string {
    return `${this.lastName}, ${this.firstName}`;
  }
}

const m = new Member

console.log(m.firstLastName)