在redux中，reducer改变状态后会发生什么？

Question

I am reading the source code of a react app , which implement OKTA user management API.

One thing that make me confused is how after the state change for example after logIn

const registration = (state = initialState, action) => {
    switch (action.type) {
        case 'LOGOUT':
            return Object.assign({}, state, {sessionToken: null, error: null});
        case 'LOGIN_ERROR':
            return Object.assign({}, state, {sessionToken: null, error: action.payload});
        case 'LOGIN_SUCCESS':
            return Object.assign({}, state, {sessionToken: action.payload, error: null});
        default:
            return state;
    }
};

I guess login page would be rendered to profile page. But here the reducer only connected to store . Then how does this work?

PS: I attached wrong code at first.

Answer 1

The react-redux plug-in is the glue between redux and react . The plug-in subscribes to the store to be called whenever the store state changes. Each time the store changes, react-redux updates all of it's connected components. This is done in a way that is optimal as to not update a component if the part of the store that changed is of no interest to that component.