title: Interface, Angular 5, Reactive Form
body: <p>I have created an interface for login and getting and error when I am trying to compile it </p>
  
  <p><strong>error :<em></strong>Type 'FormGroup' is not assignable to type 'IAuth'. Property 'email' is missing in type 'FormGroup'<br></em></p>
  
  <p><strong><p>auth.ts</p></strong></p>
  
  <pre><code>export interface IAuth{
  
      email : String;
      password : String;
  
  }
  </code></pre>
  
  <p><strong><p>login.component.ts</p></strong></p>
  
  <pre><code>import { HomePage } from './../home/home';
  import { FormBuilder, FormGroup, Validators, FormControl } from '@angular/forms';    
  import { Component } from '@angular/core';    
  import { IAuth } from '../../models/auth';
  
  
  @Component({
    selector: 'page-login',
    templateUrl: 'login.html',
  })
  
  export class LoginPage {
    userAuth : IAuth;
    constructor ( private formBuilder : FormBuilder)
                 {
                   this.userAuth = formBuilder.group({
                    email : new FormControl('',Validators.required),
                    password : new FormControl('',Validators.required)
                   });
                 }
  }
  </code></pre>