I have tried mapping reactive form properties to an object class using (Object.Assign) but it adds extra properties that doesn’t belong to the class or interface, ex:

export interface MyInterface {
    a: string |null,
    b: number|null
}

and when I submit the form I do the following:

onSubmit() {
    const mynewobject:MyInterface = Object.assign({},this.myForm.getRawValue());

    console.warn(mynewobject);
  }

but the result I receive is :

{a: 'text', b: 1, c: 'additional property from form'}

I only want to map properties a and b.

Is there a way to map only properties that belong to the class or interface?