react-dyn-tabs/src/utils/stateManagement/reducer.js

React dynamic tabs with full API

import actions from './actions.js';
import helper from '../helper';
export default function reducer(state, action) {
  switch (action.type) {
    case actions.close: {
      const {openTabIDs: arr} = state,
        removedItemIndex = arr.indexOf(action.tabId);
      if (removedItemIndex >= 0) {
        const newArr = arr.slice();
        newArr.splice(removedItemIndex, 1);
        return {selectedTabID: state.selectedTabID, openTabIDs: newArr};
      }
      return state;
    }
    case actions.open: {
      const arr = state.openTabIDs,
        tabId = action.tabId;
      if (arr.indexOf(tabId) === -1) {
        const newArr = arr.slice();
        newArr.push(tabId);
        return {selectedTabID: state.selectedTabID, openTabIDs: newArr};
      }
      return state;
    }
    case actions.refresh:
      return helper.getCopyState(state);
    case actions.active: {
      const tabId = action.tabId;
      if (state.selectedTabID !== tabId) return {selectedTabID: tabId, openTabIDs: state.openTabIDs};
      return state;
    }
    case actions.sort: {
      const arr = state.openTabIDs,
        newArr = action.tabId,
        newArrCount = newArr.length;
      if (arr.length !== newArrCount) return state;
      for (let i = 0; i < newArrCount; i++) {
        if (arr.indexOf(newArr[i]) === -1) return state;
      }
      return {selectedTabID: state.selectedTabID, openTabIDs: newArr};
    }
    default:
      throw new Error(`Undefined action type '${action.type}'`);
  }
}