seamusv/purchase.html

## purchase.html
<!DOCTYPE html>
<html>
<head>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/4.1.0/rx.all.min.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/rxjs-dom/7.0.3/rx.dom.min.js"></script>
</head>
<body>

<script type="text/javascript">
    var items = [
        "apple",
        "orange",
        "apple",
        "apple",
        "apple",
        "peach"
    ];

    var priceTable = new Rx.ReplaySubject();
    var calculator = new Rx.Subject();
    var receipt = new Rx.Subject();
    receipt.subscribe(function (x) {
                console.log("Receipt", x);
            });

    var groupedItems = Rx.Observable.from(items)
            .groupBy(function(x){return x})
            .flatMap(function(x){return x.underlyingObservable.toArray()})
            .map(function(x) {return {key: x[0], items: x}});

    Rx.DOM
            .ajax({
                url: 'prices.json',
                responseType: 'json'
            })
            .map(function (x) {
                return x.response
            })
            .flatMap(function (x) {
                return Rx.Observable.from(x)
            })
            .reduce(function (acc, item, index, source) {
                var till$ = acc[0];
                var receipt$ = acc[1];
                var name = item.name;
                var pricePoints = [];
                for (idx in item.specialOffers) {
                    var specialOffer = item.specialOffers[idx];
                    pricePoints.push([specialOffer.numOfItemsForSpecial, specialOffer.price]);
                }
                pricePoints
                        .sort(function (a, b) {
                            if (a[0] < b[0]) return -1;
                            if (a[0] > b[0]) return 1;
                            return 0;
                        });

                var subject = new Rx.Subject();
                var itemSubject = subject
                        .filter(function(x) {return x.key == name})
                        .map(function(x) {return x.items})

                till$
                        .subscribe(subject);

                var chain = new Rx.Subject();
                chain
                        .flatMap(function(x) {return Rx.Observable.from(x)})
                        .map(function(x){return {label: name, price: item.price}})
                        .do(function(x){receipt$.onNext(x)})
                        .subscribe();

                for (idx in pricePoints) {
                    var pricePoint = pricePoints[idx];
                    var numOfItemsForSpecial = pricePoint[0];
                    var price = pricePoint[1];

                    var priceSubject = new Rx.Subject();
                    var priceBuffer = priceSubject
                            .flatMap(function(x) {return Rx.Observable.from(x)})
                            .bufferWithCount(numOfItemsForSpecial)
                            .share();

                    priceBuffer
                            .filter(function(x){return x.length < numOfItemsForSpecial})
                            .subscribe(chain);
                    priceBuffer
                            .filter(function(x){return x.length == numOfItemsForSpecial})
                            .map(function(x){return {label: name + " - " + numOfItemsForSpecial + " for " + price, price: price}})
                            .do(function(x){receipt$.onNext(x)})
                            .subscribe();

                    chain = priceSubject;
                }
                itemSubject
                        .subscribe(chain);
                return [till$, receipt$];
            }, [new Rx.Subject(), new Rx.Subject()])
            .subscribe(function (subjects) {
                var till$ = subjects[0];
                var receipt$ = subjects[1];
                calculator.subscribe(till$);
                receipt$.subscribe(receipt);
                priceTable.onNext(true);
                calculator.onCompleted()
            });

    priceTable
            .flatMap(groupedItems)
            .subscribe(calculator);


</script>

</body>
</html>
	<!DOCTYPE html>
	<html>
	<head>
	<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/4.1.0/rx.all.min.js"></script>
	<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/rxjs-dom/7.0.3/rx.dom.min.js"></script>
	</head>
	<body>

	<script type="text/javascript">
	var items = [
	"apple",
	"orange",
	"apple",
	"apple",
	"apple",
	"peach"
	];

	var priceTable = new Rx.ReplaySubject();
	var calculator = new Rx.Subject();
	var receipt = new Rx.Subject();
	receipt.subscribe(function (x) {
	console.log("Receipt", x);
	});

	var groupedItems = Rx.Observable.from(items)
	.groupBy(function(x){return x})
	.flatMap(function(x){return x.underlyingObservable.toArray()})
	.map(function(x) {return {key: x[0], items: x}});

	Rx.DOM
	.ajax({
	url: 'prices.json',
	responseType: 'json'
	})
	.map(function (x) {
	return x.response
	})
	.flatMap(function (x) {
	return Rx.Observable.from(x)
	})
	.reduce(function (acc, item, index, source) {
	var till$ = acc[0];
	var receipt$ = acc[1];
	var name = item.name;
	var pricePoints = [];
	for (idx in item.specialOffers) {
	var specialOffer = item.specialOffers[idx];
	pricePoints.push([specialOffer.numOfItemsForSpecial, specialOffer.price]);
	}
	pricePoints
	.sort(function (a, b) {
	if (a[0] < b[0]) return -1;
	if (a[0] > b[0]) return 1;
	return 0;
	});

	var subject = new Rx.Subject();
	var itemSubject = subject
	.filter(function(x) {return x.key == name})
	.map(function(x) {return x.items})

	till$
	.subscribe(subject);

	var chain = new Rx.Subject();
	chain
	.flatMap(function(x) {return Rx.Observable.from(x)})
	.map(function(x){return {label: name, price: item.price}})
	.do(function(x){receipt$.onNext(x)})
	.subscribe();

	for (idx in pricePoints) {
	var pricePoint = pricePoints[idx];
	var numOfItemsForSpecial = pricePoint[0];
	var price = pricePoint[1];

	var priceSubject = new Rx.Subject();
	var priceBuffer = priceSubject
	.flatMap(function(x) {return Rx.Observable.from(x)})
	.bufferWithCount(numOfItemsForSpecial)
	.share();

	priceBuffer
	.filter(function(x){return x.length < numOfItemsForSpecial})
	.subscribe(chain);
	priceBuffer
	.filter(function(x){return x.length == numOfItemsForSpecial})
	.map(function(x){return {label: name + " - " + numOfItemsForSpecial + " for " + price, price: price}})
	.do(function(x){receipt$.onNext(x)})
	.subscribe();

	chain = priceSubject;
	}
	itemSubject
	.subscribe(chain);
	return [till$, receipt$];
	}, [new Rx.Subject(), new Rx.Subject()])
	.subscribe(function (subjects) {
	var till$ = subjects[0];
	var receipt$ = subjects[1];
	calculator.subscribe(till$);
	receipt$.subscribe(receipt);
	priceTable.onNext(true);
	calculator.onCompleted()
	});

	priceTable
	.flatMap(groupedItems)
	.subscribe(calculator);


	</script>

	</body>
	</html>