createMigrate only worked the first time, version change didn't help

[dayhaysoos]

I used migration to add an object and it worked just fine. I needed to add another object but it doesn't seem to work this time:

import { createMigrate, persistStore, persistReducer } from 'redux-persist';
import thunk from 'redux-thunk';
// import logger from 'redux-logger';
import rootReducer from './reducers/index';

import storage from 'redux-persist/lib/storage';

const migrations = {
    0: (state) => ({
        ...state,
        claudio: {}
    }),
    1: (state) => ({
        claudio: state.favorites.moves.claudio,
    })
};

const persistConfig = {
    key: 'root',
    version: 3.6,
    storage,
    migrate: createMigrate(migrations, { debug: true }),
    whitelist: [
        'settings',
        'favorites'
    ],
};

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;

const persistedReducer = persistReducer(persistConfig, rootReducer);

let store = createStore(
    persistedReducer,
    {},
    composeEnhancers(
        applyMiddleware(
            thunk,
            // logger
        ),
    ),
);

let persistor = persistStore(store);

export default { store, persistor };

When it worked the first time, the "claudio" value was "shaheen" and I ticked the version up to 1.

As you can see, I replaced shaheen with claudio and now i"m on version 3.6. With debug on, it shows the migrationKeys array is empty.

Is there anything else I should be changing to get this to work?

[dayhaysoos]

Still having issues with this. I don't think the functions inside the migrations object are being called at all

[simondell]

From my experiments, I find:

• the keys in your migrations spec must match a version used in persistConfig. I only tried integers. I assume strings work too because integer keys on objects seem to get cast to strings anyway.
• once a store or key has upgraded to the version specified in the persistConfig, it now has that version. Running the same code again will not cause the migration to run again.
• you can't "downgrade" a version (to do this, you'd have to branch your code, make all the changes in in branch, and to reset, clear your development browsers' stored data, run the app in the old branch, then switch back to the new branch)
• you can't add new keys to your store unless you also add a reducer for the new key, or perhaps add a 'whitelist' entry into the config

So, to run your migrations[1]...

import { createMigrate, persistStore, persistReducer } from 'redux-persist';
import thunk from 'redux-thunk';
import rootReducer from './reducers/index'; // this must export a store with a `claudio` key

import storage from 'redux-persist/lib/storage';

const migrations = {
    0: (state) => ({
        ...state,
        claudio: {}
    }),
    1: (state) => ({
        claudio: state.favorites.moves.claudio,
    })
};

const persistConfig = {
    key: 'root',
    version: 1, // version must match the migrations keys
    storage,
    migrate: createMigrate(migrations, { debug: true }),
    whitelist: [
        'settings',
        'favorites',
        'claudio', // if you whitelist reducers, you must include your new reducer in your list
    ],
};

//... the rest of your code looked fine