number-munchers/reducers/high-score/high-score.reducer.js

const Immutable = require('immutable');

import * as HighScoreActions from '../../actions/high-score/high-score.actions';

const initial = {
    score: 900,
    initials: []
};

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

    switch (action.action) {
        case HighScoreActions.UPDATE_INITIALS:
            return Immutable.Map(state)
                .set('initials', action.initials)
                .toObject();

        case HighScoreActions.UPDATE_SCORE:
            return Immutable.Map(state)
                .set('score', action.score)
                .toObject();
    }

    return state;
};

export default reducer;