I am creating a calculator with React and facing issues with updating my state with fetched data. The result is fetched correctly, but the application crashes as it does not wait for async fetching opreration. Could someone assist how can I combine async operation with useReducer?

My actions:

export const ACTIONS = {
  ADD_DIGIT: "add-digit",
  CHOOSE_OPERATION: "choose-operation",
  CLEAR: "clear",
  DELETE_DIGIT: "delete-digit",
  EVALUATE: "evaluate",
};

My reducer:

const reducer = (state, { type, payload }) => {
  switch (type) {
    
    ...
    some other actions
    ...
    
    case ACTIONS.CHOOSE_OPERATION:
      if (state.currentOperand == null && state.previousOperand == null) {
        return state;
      }

      if (state.currentOperand == null) {
        return {
          ...state,
          operation: payload.operation,
        };
      }

      if (state.previousOperand == null) {
        return {
          ...state,
          operation: payload.operation,
          previousOperand: state.currentOperand,
          currentOperand: null,
        };
      }

      return {
        ...state,
        previousOperand: evaluate(state),
        operation: payload.operation,
        currentOperand: null,
      };


    case ACTIONS.EVALUATE:
      if (
        state.operation == null ||
        state.currentOperand == null ||
        state.previousOperand == null
      ) {
        return state;
      }

      return {
        ...state,
        overwrite: true,
        previousOperand: null,
        operation: null,
        currentOperand: evaluate(state),
      };
  }
};

My evaluate function:

const evaluate = ({ currentOperand, previousOperand, operation }) => {
  const prev = parseFloat(previousOperand);
  const current = parseFloat(currentOperand);

  if (isNaN(prev) || isNaN(current)) return "";

  const fetchData = async () => {
    const response = await axios.post("/calculation", {
      a: prev,
      b: current,
      operator: operation,
    });
    return response.data.result;
  };
  
  let computation = "";
  const getResult = async () => {
    const response = await fetchData();
    computation = response;
  };

  return computation.toString();
};