Efficient way to initialize a nested object in Angular 8

Question

I have a User class with a nested Address class. In the component I would like to initialize an object of type User with something like let user = new User() or let user:User.

But errors are thrown, because Angular/Typescript wants me to assign values. Is there an efficient way to do this, without assigning all the empty "" values to the object.

Below the classes:

class Address {
    constructor(
        public street: string,
        public number: number,
        public suffix: string,
        public houseLetter: string,
        public city: string,
        public zipcode: string,
    ) { }
}

export class User {
    constructor(
        public id: number,
        public firstName: string,
        public lastName: string,
        public email: string,
        public address: Address,
    ) { }
}

Mustahsan · Accepted Answer · 2019-11-29 12:10:43Z

2

You can mark these parameters as optional like this:

export class User {
    constructor(
        public id?: number,
        public firstName?: string,
        public lastName?: string,
        public email?: string,
        public address?: Address,
    ) { }
}

now you can easily instantiate user object with let user = new User()

Working demo link

edited Nov 29, 2019 at 12:10

answered Nov 29, 2019 at 11:57

Mustahsan

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Comments

Yash Rami · Accepted Answer · 2019-11-29 11:53:52Z

0

you can try like this

Model

export class AddressModel {
    constructor(data?: any) {
    if (data != null) {
        this.street = data.street;
        this.number = data.number;
        this.suffix = data.suffix;
        this.houseLetter = data.houseLetter;
        this.city = data.city;
        this.zipcode = data.zipcode;
    }
 }
        public street: string = null;
        public number: number = null;
        public suffix: string = null;
        public houseLetter: string = null;
        public city: string = null;
        public zipcode: string = null;
}

TS

someFunction() {
let data = new AddressModel({data to pass}); // here we are passing the data
}

answered Nov 29, 2019 at 11:53

Yash Rami

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Comments

paul · Accepted Answer · 2019-11-29 12:05:49Z

0

I use this pattern:

export class Address {
    street: string;
    number: number;
    suffix: string;
    houseLetter: string;
    city: string;
    zipcode: string;

    constructor(values? : Partial<Address>)
    { 
        Object.assign(this, values);
    }
}

export class User {
    id: number;
    firstName: string;
    lastName: string;
    email: string;
    address: Address;
    constructor(values? : Partial<User>)
    { 
        Object.assign(this, values);
    }
}

Usage:

const p1 = new User();

const p2 = new User({
  firstName: 'paul',
  address: new Address({
    street: '1 st james street'
  })
});

answered Nov 29, 2019 at 12:05

paul

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Comments

Prashant Pimpale · Accepted Answer · 2019-11-29 13:09:54Z

0

This seems to work fine:

export class User {
  public id: number = 0;
  public firstName: string = "";
  public lastName: string = "";
  public email: string = "";
}

In TS:

user = new User();
 constructor() {
  console.log(this.user); // {"id":0,"firstName":"","lastName":"","email":""}
}

Online_Demo

answered Nov 29, 2019 at 13:09

Prashant Pimpale

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