Example session actions, store and cache w/ flummox.

SessionActions.js

var { Actions } = require('flummox');
var Promise = require('bluebird');
var assign = require('object-assign');

class SessionActions extends Actions {
	constructor(api, flux) {
		super();
		this.api = api;
		this.flux = flux;
	}

	fetchSession(username, password) {
		return this.api.auth.login(username, password).then(res => res.body);
	}
	
	login(username, password) {
		var fetchSession = this.fetchSession(username, password);
		var fetchUser = fetchSession.then(res => {
			// Normally you wouldn't have to worry about the access token but it is not set on
			// the api client until both fetchSession and fetchUser resolve.
			
			this.receiveSession(res.access_token, res.user_id);
			return this.flux.getActions('core.users').fetchUser(res.user_id);
		});
		
		return Promise.join(
			fetchSession,
			fetchUser,
			(session, user) => assign({}, session, { user }));
	}
	
	logout() {
		// No payload.
		return true;
	}
	
	receiveSession(accessToken, userId) {
		return { accessToken, userId };
	}
}

module.exports = SessionActions;

SessionCache.js

class SessionCache {
	constructor(sessionActions, sessionStore, cacheKey) {
		this.sessionActions = sessionActions;
		this.sessionStore = sessionStore;
		this.sessionStore.on('change', this._handleSessionChange.bind(this));
		this.cacheKey = cacheKey;
	}
	
	load() {
		var data = sessionStorage.getItem(this.cacheKey);

		if (data) {
			var { userId, accessToken } = JSON.parse(data);
			this.sessionActions.receiveSession(accessToken, userId);
		}
	}

	_handleSessionChange() {
		if (this.sessionStore.isLoggedIn()) {
			var data = {
				accessToken: this.sessionStore.getAccessToken(),
				userId: this.sessionStore.getUserId()
			};
			
			sessionStorage.setItem(this.cacheKey, JSON.stringify(data));
		} else {
			sessionStorage.removeItem(this.cacheKey)
		}
	}
}

module.exports = SessionCache;

SessionStore.js

var { Store } = require('flummox');

class SessionStore extends Store {
	constructor(sessionActions) {
		super();
		
		this.registerAsync(
			sessionActions.login,
			this._handleLoginBegin,
			this._handleLoginSuccess,
			this._handleLoginFailed
		);
		
		this.register(sessionActions.logout, this._handleLogout);
		this.register(sessionActions.receiveSession, this._handleLoginSuccess);

		this.state = {};
	}
	
	// Getters
	isLoading() {
		return !!this.state.loading;
	}
	
	isLoggedIn() {
		return !!this.state.accessToken;
	}
	
	getUserId() {
		return this.state.userId;
	}
	
	getAccessToken() {
		return this.state.accessToken;
	}
	
	hasErrors() {
		return !!this.state.errorMessage;
	}
	
	getErrorMessage() {
		return this.state.errorMessage;
	}

	// Handlers
	_handleLoginBegin() {
		this.replaceState({ loading: true });
	}

	_handleLoginSuccess(payload) {
		this.replaceState({
			accessToken: payload.access_token || payload.accessToken,
			userId: payload.user_id || payload.userId,
			loading: false
		});
	}

	_handleLoginFailed(err) {
		this.replaceState({
			errorMessage: err.message
		});
	}

	_handleLogout() {
		this.replaceState({ });
	}
}

module.exports = SessionStore;