如何在react redux中仅对值求和一次

// reducer.js

const initialState = {
  value: 0,
  sum: 0,
  isSummed: false
};

const reducer = (state = initialState, action) => {
  switch (action.type) {
    case 'SUM_VALUES':
      if (!state.isSummed) {
        const sum = state.value + action.payload;
        return {
          ...state,
          sum,
          isSummed: true
        };
      }
      return state;
    default:
      return state;
  }
};

export default reducer;

// actions.js

export const sumValues = (value) => {
  return {
    type: 'SUM_VALUES',
    payload: value
  };
};

// YourComponent.js

import React from 'react';
import { connect } from 'react-redux';
import { sumValues } from './actions';

const YourComponent = ({ value, sumValues }) => {
  const handleSum = () => {
    sumValues(value);
  };

  return (
    <div>
      <p>Value: {value}</p>
      <button onClick={handleSum}>Sum Values</button>
    </div>
  );
};

const mapStateToProps = (state) => {
  return {
    value: state.value
  };
};

export default connect(mapStateToProps, { sumValues })(YourComponent);

// App.js

import React from 'react';
import YourComponent from './YourComponent';

const App = () => {
  return (
    <div>
      <YourComponent />
    </div>
  );
};

export default App;