Remove the switch statement from Redux reducers!

reducer.js

const updateLocation = (state, action) => {
  return Object.assign({}, state, ...)
}

const actionHandlers = {
  'UPDATE_LOCATION': updateLocation
} 

const reducer = (state = initialState, action) => {
  const handler = actionHandlers[action.type] 
  if (!handler) return state
  return handler(state, action)
}