How to include a file upload control in an Angular2 reactive form?

Question

For some weird reason, there are just no tutorials or code samples online showing how to use Angular2 Reactive forms with anything more than simple input or select dropdowns.

I need to create a form to let users select their avatar. (Image file)

The following doesn't work. (i.e. The Avatar property never shows any value changes.)

profile.component.html:

profile.component.ts:

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup,  Validators } from '@angular/forms';
import {Config} from '../../services/config.service';
import {AuthService} from '../../services/auth.service';
import {User} from '../../models/user.model';

@Component({
  selector: 'app-profile',
  templateUrl: './profile.component.html',
  styleUrls: ['./profile.component.css']
})
export class ProfileComponent implements OnInit {
  
  authUser:User;

  profileForm : FormGroup; 

  constructor(private authService:AuthService, private fb: FormBuilder) {}
          
  createForm() {
    this.profileForm = this.fb.group({
      firstname:  [this.authUser.firstname, Validators.required ],
      lastname: [this.authUser.lastname, Validators.required ],
      email: [this.authUser.email, Validators.required ],
      avatar: [this.authUser.avatar, Validators.required ],
      password:['xxxxxx', Validators.minLength(4)] 
    });
  }
  ngOnInit() {
    this.authUser = this.authService.getAuthUser();

    this.createForm();
  } 

Answer 1

Simple answer can be found here. https://devblog.dymel.pl/2016/09/02/upload-file-image-angular2-aspnetcore/

The HTML

    <input #fileInput type="file"/>
    <button (click)="addFile()">Add</button>

Component.ts

@ViewChild("fileInput") fileInput;

addFile(): void {
let fi = this.fileInput.nativeElement;
if (fi.files && fi.files[0]) {
    let fileToUpload = fi.files[0];
    this.uploadService
        .upload(fileToUpload)
        .subscribe(res => {
            console.log(res);
        });
    }
}

The service.ts

upload(fileToUpload: any) {
    let input = new FormData();
    input.append("file", fileToUpload);

    return this.http.post("/api/uploadFile", input);
}