React Js apps / Microsoft Edge error:SCRIPT1028: Expected identifier, string or number

Question

On my react app I'm receiving this error: SCRIPT1028: Expected identifier, string or number

It seems to come from my Store.js with easy-peasy

const store = createStore({
  answers: [],
  totalPoints: 0,
  otp: "",
  loading: false,

  addAnswer: action((state, payload) => {
    const prevState = state.answers;
    const newAnswers = _.unionBy([payload], prevState, "questionNumber");

    return (state = {
      answers: newAnswers,
      totalPoints: _.sumBy(newAnswers, "selectedAnswer"),
      otp: state.otp,
    });
  }),

//**error seems to come here**
  setOtp: action((state, payload) => {
    return { ...state, ...state.answers, ...{ otp: payload } };
  }),

  setLoading: action((state, payload) => {
    return {
      ...state,
      ...state.answers,
      ...{ otp: state.otp },
      ...{ loading: payload },
    };
  }),
});

export default store;