Redux with 'shadow' master model setter / getter.

example.js

import createStore from './redux-shadow';

function reducer (state, action) {
    switch (action.type) {
        case 'init':
            this.setShadow(action.data);
            return Object.assign({}, this.getShadow());

        case 'filter':
            const filter = action.filter.toLowerCase();
            return this.getShadow()
                .filter(o => o.name.toLowerCase().indexOf(filter) > -1);

    }
}

const store = createStore(reducer);

/**
 * Test
 */
store.subscribe(() => console.log(store.getState()));

/**
 * Set data
 */
console.log('SETTING DATA');
store.dispatch({type: 'init', data: [
    {name: 'Abacus'},
    {name: 'Aaron'},
    {name: 'Dom'},
    {name: 'Sergei'}
]});

console.log('FILTERING DATA BY `A`');
store.dispatch({
    type: 'filter',
    filter: 'A'
});

console.log('FILTERING DATA BY `AA`');
store.dispatch({
    type: 'filter',
    filter: 'AA'
});

console.log('UNFILTERED');
store.dispatch({
    type: 'filter',
    filter: ''
});

redux-shadow.js

import { createStore } from 'redux';

/**
 * Wraps the redux store, so that the reducer has access to a persistent
 * this context. Try not to add things to the `this`, but instead use the
 * available functions:
 *  - setShadow( data = {} )
 *  - getShadow( )
 *
 * this.setShadow stores a passed data object out of sight for later retrieval
 * with this.getShadow().
 *
 * Useful when you have a master data model, and want to return a filtered
 * / manipulated model in response to various `dispatch` calls. Avoids the
 * need to cache the original model in a closure.
 *
 * @param {Function} reducer
 * @param {any} [initialState] @see redux docs
 * @param {Function} enhancer @see redux docs
 * @returns {Store}
 */
function createStoreWithShadow (reducers, initialState, enhancer) {
    let shadow;
    const setShadow = (data) => shadow = data;
    const getShadow = () => shadow;
    const shadowContext = {
            getShadow,
            setShadow
        };

    return createStore(reducers.bind(shadowContext), initialState, enhancer);
}

export default createStoreWithShadow;