Никита Гущин

function removeFromStructure(id) {
  return { type: REMOVE_FROM_STRUCTURE, paylodad: id }
}
function doSomething(id) {
  return { type: DO_SOMETHING, paylodad: id }
}
function commonAction(structureObject) {
  return structureObject.blockId ? removeFromStructure(id) : doSomething(id)
}

const action = {
  id: 132,
  _key: 'some key',
  _value: 564
}

return {
  ...state,
  structure: {
    ...state.structure,
    [id]: { ...(state.structure[id] || {}), ...action },
  }
}

import _ from 'lodash'

const { id, parentId } = action
// удаляем из структуры свойство с именем id
const nextStructure = _.omit(state.structure, id)
return {
  ...state,
  structure: {
    ...nextStructure,
    [parentId]: {
      ...nextStructure[parentId],
      childIds: nextStructure[parentId].childIds.filter(cId => cId !== id)
    }
  }
}

const { id, parentId } = action
// в данном случае у нас будет переменная
// const removed = state.structure[id]
// а в переменную nextStructure попадут все значения, кроме id
const { [id]: removed, ...nextStructure } = state.structure
return {
  ...state,
  structure: {
    ...nextStructure,
    [parentId]: {
      ...nextStructure[parentId],
      childIds: nextStructure[parentId].childIds.filter(cId => cId !== id)
    }
  }
}

shouldComponentUpdate(nextProps, nextState) {
    return shallowCompare(this, nextProps, nextState);
  }

const store = createStore(history, client, initialState)

store.dispatch(appActions.loadInitialData())

render((
  <Provider store={store}>
    <Router history={finalHistory}>
      {routes}
    </Router>
  </Provider>
), reactRootElement)

function loadInitialData() {
  return dispatch => axios
    .get(`${apiPrefix}/entities`)
    .then(entities => dispatch(saveEntities(entities)))
}

const myReducer = combineReducers({ connectedReducer1, connectedReducer2 })

function combinedReducer(state = initialState, action = {}) {
  switch(action.type) {
    case SOME_COMPLEX_ACTION:
      return {
         ...state,
         someProp: someOtherReducer(state.someProp, { type: OTHER_ACTION, payload: action.payload.something })
      }
    default:
      return {
         ...state,
         someProp: someOtherReducer(state.someProp)
      }
  }
}

function mapStateToProps(state) {
  const filter = state.something.filter
  const items = state.other.items
  return {
    items: filterItems(items, filter)
  } 
}
connect(mapStateToProps)(...)

// rootEntity reducer
const initialState = {
  entities: {}
}

function rootEntityReducer(state = initialState, action = {}) {
  switch(action.type) {
    case ADD_ELEMENT:
      const { targetEntityId, element } = action.payload
      const targetEntity = state.entities[targetEntityId]
      return {
        ...state,
        entites: {
          ...state.entities,
          [targetEntityId]: { ...targetEntity, elements: [ ...targetEntity.elements, element ] }
        }
      }
    default:
      return state
  }
}

// rootEntity reducer
const initialState = {
  entities: []
}

function rootEntityReducer(state = initialState, action = {}) {
  switch(action.type) {
    case ADD_ELEMENT:
      const { targetEntityId, element } = action.payload

      return {
        ...state,
        entites:  state.entities.map(
          entity => entity.id !== targetEntityId
            ? entity
            : { ...entity , elements: [ ...entity.elements, element ] }
        )
      }
    default:
      return state
  }
}

functiob action1Creator() {
  return (dispatch, getState) => {
    fetch(...)
      .then(JSON.parse)
      .then((response) => dispatch(action2Creator(response)))
    ;
  };
}

function action2Creator(response) {
  return { type: 'SOME', data: response.data[12] };
}