How to get the initial state of the reducer?

Question

redux

How to get the initial state of the reducer?
Here is an example code, but for some reason it doesn't work

const initialState = {

  message  : false,

  key: null

}


const notification = (state = initialState , action) => {

  switch( action.type ){

    case "UPDATE_NOTIFICATION":
      return Object.assign({}, state, action.payload );

    case "RESET_NOTIFICATION":
      return initialState;

    default :  return state;

  }
}

export default notification;