Typescript set property value from other properties during initialization for objects read via respo-CodePudding

I have a simple class

export class MyObj{
  prop1: string;
  prop2: string;
  prop3: string;
}

I am reading data into it from backend using HttpClient:

this.httpClient.get<MyObj[]>(`backendUrl`).subscribe(
  (response: MyObj[]) => {
    //...some code...
  }
);

Now I want to have a prop4 in this class that will get its value from other properties during initialization and will be available in the above response array. To achieve this I changed the class code to below but it didn't work. How can I achieve what I want?

export class MyObj{
  prop1: string;
  prop2: string;
  prop3: string;
  prop4: string;

  constructor(prop1, prop2, prop3) {
    this.prop1 = prop1;
    this.prop2 = prop2;
    this.prop3 = prop3;
    this.prop4 = prop1   prop2   prop3;
  }
}

CodePudding user response：

try with this:

export class MyObj{
  constructor(public prop1, public prop2, public prop3, private prop4) {
     this.prop4 = this.prop1   this.prop2   this.prop3;
  }
}

the public/private can be changed according to your needs

EDIT: With @jonrsharpe commentary, I was aware of the mistake... But if it doesn't work, I'm going to give you another possible solution:

export class MyObj{
  prop1: string;
  prop2: string;
  prop3: string;
  prop4?: string;
}

this.httpClient.get<MyObj[]>(`backendUrl`).subscribe(
  (response: MyObj[]) => {
     response.map( 
        _item => _item.prop4 = _item.prop1 _item.prop2 _item.prop3
     );
    //...some code...
  }
);

CodePudding user response：

Try with

Object.assign(this.prop4, this.prop1, this prop2, this.prop3);