What is the purpose of FormBuilder?

FormBuilder is used as syntactic sugar for easily creating instances of a FormControl, FormGroup, or FormArray. This is helpful to reduce the amount of boilerplate needed to build complex reactive forms. It is available as an injectable helper class of the @angular/forms package.

For example, the user profile component creation becomes easier as shown here.

export class UserProfileComponent {
profileForm = this.formBuilder.group({
  firstName: [''],
  lastName: [''],
  address: this.formBuilder.group({
    street: [''],
    city: [''],
    state: [''],
    zip: ['']
  }),
});
constructor(private formBuilder: FormBuilder) { }
}