number-munchers/reducers/board/grid.reducer.js

const Immutable = require('immutable');

import * as GridActions from '../../actions/board/grid.actions';

const initial = [];

const reducer = (state = initial, action) => {
    if (action.type !== GridActions.GRID_ACTION) {
        return state;
    }

    if (action.action === GridActions.UPDATE) {
        return Immutable.List(action.values).toArray();
    }

    return state;
};

export default reducer;