user-model.js

class User {
  constructor(getState, rootUpdater) {
    this._getState = getState;
    this._rootUpdater = rootUpdater;

    this.name = '';
    this.surname = '';
  }

  _setValue = (value = {}) => {
    this._rootUpdater({
      user: {
        setName: this.setName,
        setSurname: this.setSurname,
        ...this._getState().user,
        ...value
      }
    });
  };

  setName = (name = '') => {
    this._setValue({name});
  }

  setSurname = (surname = '') => {
    this._setValue({surname});
  }

}