iswhoa/public/scripts/controllers/gamestate.js

const GAME_STATE_KEY = "gameState";

class GameState {
    getQuestionChoice(qId) {
        let savedItem = this._readGameState();
        if (qId in savedItem) {
            return savedItem[qId];
        }
        return null;
    }

    setQuestionChoice(qId, cId, isRight) {
        let savedItem = this._readGameState();
        savedItem[qId] = {cId: cId, isRight: isRight};
        localStorage.setItem(GAME_STATE_KEY, JSON.stringify(savedItem));
    }

    clearChoices() {
        localStorage.removeItem(GAME_STATE_KEY);
    }

    getSummary() {
        let savedItem = this._readGameState();
        let summary = { totalAnswered: 0, totalRight: 0 };

        for (let k in savedItem) {
            summary.totalAnswered++;
            if (savedItem[k].isRight) {
                summary.totalRight++;
            }
        }

        return summary;
    }

    _readGameState() {
        let savedItem = localStorage.getItem(GAME_STATE_KEY);
        if (savedItem === null) {
            return {};
        } else {
            return JSON.parse(savedItem);
        }
    }
}

export let gameState = new GameState();