Arolla Jam Code Kata Microservices - 30/11/2021

kata-microservice.js

class MessageBus {
    constructor() {
        this.listeners = [];
    }
    subscribe(listener) {
        this.listeners.push(listener);
    }
    send(message) { 
        this.listeners.forEach(function(listener) {
            listener.onMessage(message);
        });
    }
}
class Booking {
    constructor(msgBus) {
        this.msgBus = msgBus;
        this.msgBus.subscribe(this);
    }
    onMessage(message) {}
    book(seats_count) {
        console.log("Booking.book(): seats_count='" + seats_count + "'");
        this.msgBus.send({
            name: "booking_placed",
            seats_count: seats_count
        });
    }
}
class Inventory {
    constructor(msgBus, capacity) {
        this.msgBus = msgBus;
        this.seats_left = capacity;
        this.msgBus.subscribe(this);
    }
    onMessage(message) {
        if (message.name === "booking_placed") {
            this.reserve_seats(message.seats_count);
        }
    }
    reserve_seats(seats_count) {
        console.log("Inventory.reserve_seats()");
        if (this.seats_left < seats_count) {
            console.log("ERROR: Inventory.reserve_seats(): not enough seats left");
            this.msgBus.send({
                name: "capacity_exceeded"
            });
        }
        this.seats_left -= seats_count;
        this.msgBus.send({
            name: "ticket_booked",
            seats_count: seats_count
        });
    }
}
class Ticketing {
    constructor(msgBus) {
        this.msgBus = msgBus;
        this.msgBus.subscribe(this);
    }
    onMessage(message) {
        if (message.name === "ticket_booked") {
            this.send_ticket(message.seats_count)
        }
    }
    send_ticket(seats_count) {
        console.log("Ticketing.send_ticket(): seats_count='" + seats_count + "'");
    }
}
function main() {
    msgBus = new MessageBus();
    inventory = new Inventory(msgBus, 30);
    ticketing = new Ticketing(msgBus);
    booking = new Booking(msgBus);
    booking.book(2);
}
main();