redux-state-sync/example_immutable/src/reducers/visibilityFilter.js

A middleware for redux to sync state in different tabs

const visibilityFilter = (state = 'SHOW_ALL', action) => {
    switch (action.type) {
        case 'SET_VISIBILITY_FILTER':
            return action.filter;
        default:
            return state;
    }
};

export default visibilityFilter;