upload file using Angular Reactive FormGroup and JavaScript FormData

This is a very quick and easy solution.
1. Create express back end with express-fileupload middleware
2. Create a FormGroup in your component
3. Create a file selection button in your template, and pass selected file to your FormGroup using FormGroup.patchValue()
4. Pass name-values from FormGroup to FormData
5. Submit FormData in your http.post() call