Save and load the Redux state with ease.
My focus has left the node / react ecosystem and this module has got a new home over at react-stack!
- Flexible storage engines
- localStorage: based on window.localStorage
- Or for environments without
Promisesupport localStorageFakePromise
- Or for environments without
- reactNativeAsyncStorage: based on
react-native/AsyncStorage
- localStorage: based on window.localStorage
- Flexible state merger functions
- simple: merge plain old JS structures (default)
- immutablejs: merge plain old JS and Immutable objects
- Storage engines can be async
- Load and save actions that can be observed
- Various engine decorators
- Black- and whitelist actions from issuing a save operation
npm install --save redux-storage
And you need to install at least one redux-storage-engine, as redux-storage is only the "management core".
import * as storage from 'redux-storage'
// Import redux and all your reducers as usual
import { createStore, applyMiddleware, combineReducers } from 'redux';
import * as reducers from './reducers';
// We need to wrap the base reducer, as this is the place where the loaded
// state will be injected.
//
// Note: The reducer does nothing special! It just listens for the LOAD
// action and merge in the provided state :)
// Note: A custom merger function can be passed as second argument
const reducer = storage.reducer(combineReducers(reducers));
// Now it's time to decide which storage engine should be used
//
// Note: The arguments to `createEngine` are different for every engine!
import createEngine from 'redux-storage-engine-localstorage';
const engine = createEngine('my-save-key');
// And with the engine we can create our middleware function. The middleware
// is responsible for calling `engine.save` with the current state afer
// every dispatched action.
//
// Note: You can provide a list of action types as second argument, those
// actions will be filtered and WON'T trigger calls to `engine.save`!
const middleware = storage.createMiddleware(engine);
// As everything is prepared, we can go ahead and combine all parts as usual
const createStoreWithMiddleware = applyMiddleware(middleware)(createStore);
const store = createStoreWithMiddleware(reducer);
// At this stage the whole system is in place and every action will trigger
// a save operation.
//
// BUT (!) an existing old state HAS NOT been restored yet! It's up to you to
// decide when this should happen. Most of the times you can/should do this
// right after the store object has been created.
// To load the previous state we create a loader function with our prepared
// engine. The result is a function that can be used on any store object you
// have at hand :)
const load = storage.createLoader(engine);
load(store);
// Notice that our load function will return a promise that can also be used
// to respond to the restore event.
load(store)
.then((newState) => console.log('Loaded state:', newState))
.catch(() => console.log('Failed to load previous state'));They all are published as own packages on npm. But as a convention all engines share the keyword redux-storage-engine, decorators can be found with redux-storage-decorator and mergers with redux-storage-merger. So it's pretty trivial to find all the additions to redux-storage you need 😄
redux-storage will trigger actions after every load or save operation from the underlying engine.
You can use this, for example, to display a loading screen until the old state has been restored like this:
import { LOAD, SAVE } from 'redux-storage';
function storageAwareReducer(state = { loaded: false }, action) {
switch (action.type) {
case LOAD:
return { ...state, loaded: true };
case SAVE:
console.log('Something has changed and written to disk!');
default:
return state;
}
}If you pass an array of action types as second argument to createMiddleware,
those will be added to a internal blacklist and won't trigger calls to
engine.save.
import { createMiddleware } from 'redux-storage'
import { APP_START } from './constants';
const middleware = createMiddleware(engine, [ APP_START ]);If you want to whitelist all actions that are allowed to issue a engine.save,
just specify them as third argument.
import { createMiddleware } from 'redux-storage'
import { SHOULD_SAVE } from './constants';
const middleware = createMiddleware(engine, [], [ SHOULD_SAVE ]);The MIT License (MIT)
Copyright (c) 2015 Michael Contento
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