6 arguments expected, but 0 received.ts(2554)

Question

I am following a course that uses angular version 4 however I decided to use version 12.2.10 of angular CLI and version 14.18.1 of Node.

I created a 'contact.ts' model:

export class Contact{
    private id:number;
    private nom:string;
    private prenom:string;
    private email:string;
    private tel:string;
    private photo:string;

    constructor(id:number,nom:string,prenom:string,email:string,tel:string,photo:string){
        this.id = id;
        this.nom = nom;
        this.prenom = prenom;
        this.email = email;
        this.tel = tel;
        this.photo = photo
    }

    
}

and I'm trying to instantiate a new class of it here 'NewContactComponent.ts':

import { Component, OnInit } from '@angular/core';
import { Contact } from 'src/model/model.contact';

@Component({
  selector: 'app-new-contact',
  templateUrl: './new-contact.component.html',
  styleUrls: ['./new-contact.component.css']
})
export class NewContactComponent implements OnInit {

  contact:Contact=new Contact();

  constructor() { }

  ngOnInit(): void {
    
  }

}

but impossible to do that. Here is the error message:

6 arguments expected, but 0 received.ts(2554)
model.contact.ts(10, 17): Aucun argument pour 'id' n'a été fourni.
(alias) new Contact(id: number, nom: string, prenom: string, email: string, tel: string, photo: string): Contact
import Contact

Answer 1

You either need to pass in all the variables into the Contact class new Contacts(id, nom, prenom, email, tel, photo) or mark all the variables as optional.

You can also simplify the constructor, see below.

export class Contact{
  constructor(
    private id?: number,
    private nom?: string,
    private prenom?: string,
    private email?: string,
    private tel?: string,
    private photo?: string
  ){ }
}

two things to note here, by adding ? it will make that variable optional. Second thing to note is that by marking the variables as private or public, you can avoid needing to set each variable inside the constructor, typescript will do this form you when it compiles.