text: const INIT_STATE = {
      isSignedIn: null,
  };
  
  export default (state = INIT_STATE, action) => {
      switch (action.type) {
          case 'SIGN_UP':
              return { ...state, isSignedIn: action.payload.jwt };
          case 'CUSTOM_SIGN_IN':
              return { ...state, isSignedIn: action.payload.jwt };
          default:
              return state;
      }
  };
  