javascript_practice/hw11/redux.js

function shoppingCartReducer(state, {type, what, howMach, money}) {
	if(!state) {
		return {
			videoCards: {
				amount: 100,
				price: 180
			},
			processors: {
				amount: 100,
				price: 120
			},
			memory: {
				amount: 100,
				price: 80
			},
			totalMoney: 0
		}
	}
	if(type === 'buy') {
		return {
			...state,
			[what]: {
				amount: (state[what].amount - howMach < 0 || money < state[what].price) ? state[what].amount : state[what].amount - howMach,
				price: state[what].price
			},
			totalMoney: (state[what].amount - howMach < 0 || money < state[what].price) ? state.totalMoney : (howMach * money) + state.totalMoney
		}
	}
	return state;
}

function createStore(reducer){
	let state       = reducer(undefined, {});
	let cbs         = [];

	const getState  = () => state;
	const subscribe = cb => (cbs.push(cb),
		() => cbs = cbs.filter(c => c !== cb));

	const dispatch  = action => {
		const newState = reducer(state, action);
		if (newState !== state){
			state = newState;
			for (let cb of cbs)  cb();
		}
	}

	return {
		getState,
		dispatch,
		subscribe
	}
}

const store = createStore(shoppingCartReducer);

store.subscribe(() => storeBlock.innerText = JSON.stringify(store.getState()));

const buyAction = (what, howMach, money) => ({type: 'buy', what: `${what}`, howMach, money});

store.dispatch(buyAction('videoCards', 0, 0));

buy.addEventListener('click', () => {
	let what = goods[goods.options.selectedIndex].value;
	let howMach = amount.value;
	let moneyVal = money.value;
	store.dispatch(buyAction(what, howMach, moneyVal));
})