ng2 file upload - send file and form at the same time

Question

I got simple form like:

<form [formGroup]="registrationForm" (ngSubmit)="onSubmit()">
 <label>Adres</label>
                    <input type="text" formControlName="address" class="form-control"
                      [ngClass]="{ 'is-invalid': submitted && f.address.errors }" />
                    <div *ngIf="submitted && f.address.errors" class="invalid-feedback">
                      <div *ngIf="f.address.errors.required">Address is required</div>
                    </div>
    
<input type="file" name="image" ng2FileSelect [uploader]="uploader"
             accept="image/x-png,image/gif,image/jpeg" />
<button class="btn btn-primary mr-1 btn-block" [disabled]="!uploader.getNotUploadedItems().length">Send</button>
</form>

and there is my .ts onSubmit()

  onSubmit() {
    this.submitted = true;
    if (this.registrationForm.invalid) {
      return
    } 
    this.accidentFormService.saveAccidentForm(this.registrationForm.value).subscribe(
      res => {
      console.log(res);
      },
      err => console.error(err)
    );
   // alert(JSON.stringify(this.registrationForm.value));
  }

When code is outside form tag and button got (click)="uploader.uploadAll()" it works fine but when it is inside form tag it doesn't works.

How can I send form and file at the same time? I got two other api routes for Form and File.