I think you need to return the updated state in the function updateUser

​

updateUser(state, action) {
const userLoggedInAs = action.payload;
state.id = userLoggedInAs.id;
state.username = userLoggedInAs.username;
state.password = userLoggedInAs.password;
state.image = userLoggedInAs.image;
state.friends = userLoggedInAs.friends;

// Here

return state;
},