This looks like mess. Its so difficult to maintain any software with this kind of scattered components. It is always a better idea to sperate out logical things into well defined directory structure. We will do this in a moment. Checkout the next Pull request

unmanaged-index.jsx

import {combineReducers, createStore} from 'redux';

const usersReducer = (usersState = [], action) => {
  const new_state = Object.assign([], usersState);
  switch (action.type) {
    case 'UPDATE_USER': {
      var updateable_record = new_state.find((item) => item.id === action.payload.id);
      new_state[new_state.indexOf(updateable_record)] = Object.assign({}, updateable_record, action.payload);
      break;
    }

    case 'DELETE_USER': {
      var updateable_record = new_state.find((item) => item.id === action.payload.id);
      new_state.splice(new_state.indexOf(updateable_record), 1);

      // Remember sometime one action can have consequences in multiple Models
      // For eg: when user is deleted, it should also delete its belongings like articles.
      // Since, Redux routes the actions_types to every reducers in the chain, so you need to catch this
      //   action_type in articlesReducer as well and execute.
      break;
    }
  }
  return new_state;
};

const articlesReducer = (articlesState = [], action) => {
  const new_state = Object.assign([], articlesState);
  switch (action.type) {
    case 'UPDATE_ARTICLE': {
      var updateable_record = new_state.find((item) => item.id === action.payload.id);
      new_state[new_state.indexOf(updateable_record)] = Object.assign({}, updateable_record, action.payload);
      break;
    }

    case 'DELETE_ARTICLE': {
      var updateable_record = new_state.find((item) => item.id === action.payload.id);
      new_state.splice(new_state.indexOf(updateable_record), 1);
      break;
    }

    case 'VIEW_ARTICLE': {
      var updateable_record = new_state.find((item) => item.id === action.payload.id);
      new_state[new_state.indexOf(updateable_record)] = Object.assign({}, updateable_record, action.payload);
      updateable_record.viewCount = updateable_record.viewCount + 1;
      break;
    }
  }
  return new_state;
};

const reducers = combineReducers({
  users: usersReducer,
  articles: articlesReducer
});

const store = createStore(reducers, {
  users: [
    {id: 1, first_name: 'John', last_name: 'Kelly', age: 34, email: 'john@sedd.com'},
    {id: 2, first_name: 'Peter', last_name: 'Kelly', age: 34, email: 'john@sedd.com'},
    {id: 3, first_name: 'Ramesh', last_name: 'Chapagain', age: 34, email: 'chaps@sedd.com'},
    {id: 4, first_name: 'Dinesh', last_name: 'Banjade', age: 34, email: 'banz@sedd.com'},
  ],
  articles: [
    {id: 1, author_id: 1, title: 'Beautiful country Nepal', body: "Lorem Ipsom", viewCount: 0},
    {id: 2, author_id: 1, title: 'Beautiful country Nepal', body: "Lorem Ipsom", viewCount: 1},
    {id: 3, author_id: 3, title: 'When I visited Dharan', body: "Lorem Ipsom", viewCount: 0},
    {id: 4, author_id: 4, title: 'My trip to Everest Basecamp', body: "Lorem Ipsom", viewCount: 0}
  ],
});

store.subscribe(() => {
  // I am listening
  console.log(store.getState());
});




// Logging part

store.dispatch({type: 'UPDATE_USER', payload: {id: 1, first_name: 'Dipesh Kishor', last_name: 'Bhattarai'}});
console.log('------------------ Updated USER with id: 1 ---------------------------');
store.dispatch({type: 'DELETE_USER', payload: {id: 3}});
console.log('----------------------------- Deleted User with id: 3 --------------------------------------');


store.dispatch({type: 'UPDATE_ARTICLE', payload: {id: 1, title: 'Blizzard in desert'}});
console.log('------------------ Updated Article ID: 1 ---------------------------');
store.dispatch({type: 'DELETE_ARTICLE', payload: {id: 4}});
console.log('------------------ Deleted Article with id: 4 ---------------------------');
store.dispatch({type: 'VIEW_ARTICLE', payload: {id: 3}});
console.log('------------------ View update for ID: 3 ---------------------------');

// Output in Browser Console
// Object {users: Array[4], articles: Array[4]}
// ------------------ Updated USER with id: 1 ---------------------------
// Object {users: Array[3], articles: Array[4]}
// ----------------------------- Deleted User with id: 3 --------------------------------------
// Object {users: Array[3], articles: Array[4]}
// ------------------ Updated Article ID: 1 ---------------------------
// {users: Array[3], articles: Array[3]}
// ------------------ Deleted Article with id: 4 ---------------------------
// Object {users: Array[3], articles: Array[3]}
// ------------------ View update for ID: 3 ---------------------------