dec.ts

export interface FormFieldParams {
  form: any
  field: string
}


const applySetterAndGetter = <T extends Function>(component: T, params: FormFieldParams): T => {
  let options = {
    get: () => {
      return params.form.payload()[params.field]
    },
    set: (value: any) => {
      params.form.updateValue({name: params.field, value})
    }
  }
  Object.defineProperty(component.prototype, params.field, options);
  return component
}

export const FormField = <T extends Function>(form: FormAccess, field: string): Function => {
  return function(target: T) {
    return applySetterAndGetter(target, {form, field})
  }
}